Welcome to the 10ticks Maths Dictionary.

Looking for a specific maths definition? You can use the 10ticks Online Maths Dictionary to find it. The dictionary contains maths words, maths definitions, maths formulae, pictures, diagrams, tables, and examples to help you understand maths.

The dictionary has been created by maths teachers with over 100 years of combined experience, offering the most comprehensive maths definitions. This dictionary is designed for children and parents who need an easy-to-use, easy-to-understand maths resource all in one place.

Browse the definitions using the letters below

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Words beginning with the letter A

Abacus
Old calculating device made up of a frame of parallel wires on which beads are hung.The wires represent place value (units, tens, hundreds etc) and beads are moved to the top of each wire to show the digits of a particular number.

Abscissa
The x-coordinate of a point in coordinate geometry. For example, a point with coordinates (2, 1) has an abscissa of 2. This is the horizontal distance of that point from the y-axis.

Absolute value
The value of a number regardless of its sign. May also be called the modulus. For example the numbers -5 and 5 have the same absolute value which is written 5.

Acceleration
The rate of change of the velocity of a moving body. Usually measured in metres per second per second(ms-2). The average acceleration (a) of an object travelling in a straight line over a period of time (t) may be calculated by the following formula:

A negative answer shows the object is slowing down (decelerating).

Accuracy
Measure of how precise a number is. Degree of accuracy depends on how many figures or decimal places are used in rounding off, or to how many significant figures a number is expressed.

Acre
Measure of land equal to 4,840 square yards.

Acute angle
A turn that is less than a quarter of a circle, that is between 0o and 90o.

Combining of two numbers to form a sum, for example 6 + 3 = 9. One of the four basic operations of arithmetic (the other three are subtraction, multiplication and division).

Pair of angles meeting at a corner (vertex) and sharing a common arm. If two adjacent angles lie on the same side of a straight line they add up to 180o.

a and b are adjacent angles.

Side next to a given angle in a right-angled triangle, but not the hypotenuse. The third side is the opposite to the given angle.

Algebra
Branch of mathematics in which properties of numbers are studied by using symbols (usually letters) to represent unknown quantities and variables. Often involves the use and rearranging of equations. For example
(x + y)2 = x2 + 2xy + y2
is true for all values of x and y. If for instance x = 2 and y = 5,
(2 + 5) 2 = 22 + 2(2x5) + 52 = 49.

Algebraic fraction

Fraction in which letters are used to stand in for numbers. It is possible to factorize or simplify these fractions.

ab = gh.

Algorithm
Series of steps used to solve a problem, for example a flow chart.

Alphametic
A cryptarithm in which the letters, which represent distinct digits, form related words or meaningful phrases.

Alternate angles
Pair of angles that lie on opposite sides and at opposite ends of a transversal (a line that cuts two or more lines in the same plane).

The alternate angles formed by a transversal across a pair of parallel lines are equal.

ao = bo.

Altitude
Perpendicular distance from a corner (vertex) of a figure to the base (the side opposite the vertex).

Amicable numbers
Two numbers are said to be amicable if each is equal to the sum of the proper divisors of the other.

AND rule
Rule used to find the combined probability of two or more independent events happening at the same time, or one after the other.
P(Event 1 AND Event 2) = P(Event 1) x P(Event 2).
Two coins are thrown, what is the probability they both land on Heads?
P(Coin 1 = H AND Coin 2 = H) = P(Coin 1 = H) x P(Coin 2 = H)
P(Coin 1 = H AND Coin 2 = H) = x =

Angle
Pair of rays that end at the same point but do not lie on the same line. Angles are measured in degrees or radians. Angles less than 90o are called acute angles, angles that are exactly 90o are called right angles, angles greater than 90o but less than 180o are called obtuse angles, and angles greater than 180o but less than 360o are called reflex angles. A protractor can be used to measure angles.<

Annulus
Plane area between two concentric circles, making a flat ring.

Anticlockwise
Direction of rotation, opposite to clockwise.

Apex
Highest point of a triangle, cone or pyramid.

Approximation
Rough estimate of a given value.

Arabic numerals
The symbols 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9, adopted by Europeans during the Middle Ages in place of Roman numerals.

Arc
Section of a curved line or circle. A circle has three kids of arc: a semicircle, which is exactly half of the circle; minor arcs, which are less than the semicircle; and major arcs which are greater than the semicircle. The arcs of a circle are measured in degrees, according to the angle formed by joining its two ends to the centre of the circle.

If the angle subtended at the centre is x, then

Remember the circumference of the circle is 2πr.

Arc minute, Arc second
Units for measuring small angles. An arc minute (symbol æ), is one-sixtieth of a degree, and an arc second (symbol ô), is one-sixtieth of an arc minute.

Area
Size of a surface, measured in square units.
.

Arithmetic
Area of mathematics concerned with numbers and their properties. The basic operations of arithmetic are addition, subtraction, multiplication and division. Raising to powers (for example, squaring or cubing a number), the extraction of roots, percentages, fractions and ratios are developed from these operations.

Arithmetic mean
Average of a set of numbers, calculated by adding together the numbers and then dividing by how many numbers there are.
E.g. The mean of 3, 4 and 5 would be (3 + 4 + 5)/3
12/3 = 4

Arithmetic progression
Sequence of terms or numbers that have a common difference between each number in that sequence. For example, 3, 9, 15, 21, 27, 33,à.. is an arithmetic progression with a common difference of 6. May also be called an arithmetic sequence.

Array
Group of numbers or letters arranged in rows and columns.

Associative operation
Operation in which the outcome is not affected by the grouping of the numbers or symbols in the sum. Addition and multiplication are associative operations, but subtraction and division are not.

Asymptote
Found in coordinate geometry, this is a straight line that a curve approaches more and more closely but never touches.

Here the curve approaches both axes but never touch them. The two axes are the asymptotes.

Automorphism
An isomorphism from a set onto itself.

Average
Typical member of a set of data, usually the arithmetic mean. Average may also refer to the median and the mode.

Axiom
Principle assumed to be true, upon which theorems are proved by using logical deduction, for example, two straight lines cannot enclose a space.

Axis
One of two reference lines used to locate a point on a graph. The horizontal axis is usually called the x-axis and the vertical axis is usually called the y-axis.

Also refers to the imaginary line about which an object may be said to be symmetrical (axis of symmetry), or the line about which an object may revolve (axis of rotation).

Any number used to get the sum or total. Using the following sum as an example, 2 + 7 = 9. The numbers two and seven are both addends, and nine is the total

Next To. This can apply to many things, for example,angles that are next to each other or sides of a shape that are next to each other.

Align
Arrange in a line, or to align the edges/centers of shapes in accordance with a given point.

Amount
Quantity, number, total, or sum of something.

A.M.
A time of the day that is in the morning,i.e. after midnight but before midday.

Analogue Clock
A regular clock, with the numbers one to twelve around the edges and two hands telling the time in minutes and hours.

Annual
Something that happens only once a year, for example, your birthday, Christmas, Easter, Valentines Day, etc.

Arms (of Angles)
The two lines that meet at a certain point to create n angle. It does not matter what type of angle it is.

Asscending Order
To arrange a set of items from smallest to largest. his can be numeric values, shapes, etc.

Asymmetry (Asymmetric)
A shape that does not have both sides the same, the opposite of Symmetry

Attribute
A characteristic of something, for example, its shape or colour, etc.

Algebraic Expression
An expression containing at least one variable

Ascending
From lowest to highest, for example, 100, 101, 102...110

Words beginning with the letter B

Ball
A sphere together with its interior.

Bar chart
Way of displaying data, using vertical or horizontal bars. The heights or lengths of the bars are proportional to the amounts they represent.

Base
Number of different single-digit symbols used in a number system. In the decimal counting system the base is 10; in the binary number system the base is 2.

Base
In geometry, the line or area on which a solid or polygon stands.

Base
In the expression xy, x is called the base and y is the exponent.

Bayes's Rule
A rule for finding conditional probability.

Bearing
Path of a moving object,or direction of a fixed point, observed from a point on the Earth, expressed as an angle from the north. Bearings are taken by compass and are measured in degrees. They have three figures e.g. 047o, 265o, 004o
.
Here the bearing of A from B is 65o.
The Bearing of B from A is 245o. The bearing B to A is the back bearing of A to B.

Billion
Internationally recognized number represented by 1 followed by 9 zeros. 1 000 000 000. The UK billion is 1 000 000 000 000 or a million million.

Bimodal
Having two distinct peaks of frequency distribution in statistics.

Binary number system
Number system to the base two, used in electronics and computing. All binary numbers are written using the digits 0 and 1 and can be used as a code to represent data or instructions by any device that can exist in two different states.
01 = 1
10 = 2
11 = 3
100 = 4
101 = 5
110 = 6
111 = 7
1000 = 8 etc.

Binomial
Algebraic expression that has two variables represented by letters, for example x = y or x û y.

Binomial coefficient
The coefficients of x in the expansion of (x+1) .

Bisect
To cut or divide into two equal parts.

Bisector
Line that bisects another line or an angle.

Bit
A binary digit.

Block graph
Diagram used in statistics in which frequency is represented by the height of the blocks.

Bound
Number that is smaller or larger than a given set of numbers.

Boundary
Line enclosing a shape, also called the perimeter.

Bracket
Sign that indicates which part of a calculation should be performed first.
3 x (4 + 2)
= 3 x 6
= 18

Thickness, also called the width.

Byte
The amount of memory needed to represent one character on a computer, typically 8 bits.

Balance
Means having the same weight or mass on either side. It is also the name for a weighing device using a beam

Bi-
The prefix meaning two or twice

Brackets
A pair of symbols used to enclose sections of maths equations
Brackets - ( )
Square Brackets - [ ]
Braces - { }

Words beginning with the letter C

Calculator
Electronic device used for performing numerical calculations,as well as computing squares and roots and some statistical and trigonometric functions.

Calculus
Area of maths that allows the manipulation of continuously varying properties. Integral calculus is used to add together the effects of continuously varying quantities, and differential calculus deals in a similar way with rates of change.

Caliban puzzle
A logic puzzle in which one is asked to infer one or more facts from a set of given facts.

Cancel
To simplify a ratio or fraction by dividing both numerator and denominator by the same variable or number.
For example = .

Capacity
Volume of liquid that a container may hold. May be measured in litres and millilitres, or pints and gallons.

Cardinal number
One of the series of numbers 0, 1, 2, 3, 4, 5, à. . These numbers relate to quantity rather than order. Ordinal numbers relate to order, first, second, third.

Cardioid
A heart-shaped curve traced out by a point on the circumference of a circle, resulting from the circle rolling around the edge of another circle of the same diameter.

Cartesian coordinate
One of a pair of numbers used to define the position of a point by its perpendicular distance from two axes, or reference lines, drawn at right angles to each other.

Here the coordinate is (2, 3).

Celsius
Temperature scale in which freezing point is zero degrees and boiling point is one hundred degrees. Previously called Centigrade.

Centimetre
Metric unit of length equal to one hundredth of a metre. i.e. 100 centimetres = 1 metre. The symbol for this measurement is cm.

Centre of enlargement
Focal point of an enlargement.
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Central angle
An angle between two radii of a circle.

Centroid
The centre of mass of a figure. The centroid of a triangle is the intersection of the medians.

Cevian
A line segment extending from a vertex of a triangle to the opposite side.

Chance
The probability or likelihood of an event occurring, expressed as a percentage or fraction.

Characteristic
The whole-number part of a logarithm.

Characteristic
The rule by which a set is formed, or the feature that distinguishes the members of a set from other objects.

Chord
Straight line joining any two points on a curve. The cord that passes through the centre of a circle is its diameter.

Circle
A perfectly round shape, the path of a point that moves so as to keep a constant distance from a fixed point, the centre. Each circle comprises a radius, a circumference, diameters, chords, tangents, sectors and segments. The ratio of the distance all around the circle (the circumference) to the diameter is an irrational number called π (pi), roughly equal to 3.1416. A circle of radius r and diameter d has a circumference C = πd or C = 2 πr, and an area A = πr2.

Circular cone
A cone whose base is a circle.

Circumference
The line that encloses a curved plane figure, such as a circle or an ellipse. The circumference of a circle is given by πd or 2 πr, where d is the diameter, r is the radius, and π is the constant pi.

Circumcentre
The circumcentre of a triangle is the centre of the circumscribed circle.

Circumcircle
The circle circumscribed about a figure. A circle that passes through all the vertices of the figure.

Circumscribe
To surround a figure with a circle that passes through all the vertices of the figure. Only certain shapes may be circumscribed.

Cissoid
A curve with equation y2 (a-x)=x3.

Class
Another name for a set.

Classify
To put into separate classes or sets.

Class interval
In statistics the range of each class of data, used when dealing with large amounts of data.

Clockwise
The direction in which the hands of a clock turn.

Closed
Descriptive of a set of data for which an operation performed on any members of the set gives a result that is also a member of the set.

Coefficient
The number part in front of an algebraic term, signifying multiplication. In general algebraic expressions, coefficients are represented by letters that may stand for numbers.
In 4x3 - 6x2 + 5x, the coefficient of x3 is 4 and the coefficient of x2 is -6.

Collinear
Lying on the same straight line. A, B and C are collinear.

Column
A vertical list of numbers or terms.

Combination
A selection of a number of objects from some larger number of objects when no account is taken of order within any one arrangement. For example, 1, 2, 3 and 2, 1, 3 are regarded as the same combination of three digits from 1, 2, 3, 4.
The number of ways of selecting r objects from a group of n is given by

where ! is the factorial of a number.

Combined probability
Probability associated with the occurrence of two or more events, either of their all taking place at the same time, or of one event taking place but not the others, or of none of the events taking place.
If the probability of winning one raffle is r1 and the probability of winning a different raffle is r2, then the combined probability of winning both raffles is given by r1 x r2 (AND Rule); the combined probability of winning one raffle or the other, but not both, is given by r1 + r2 (OR Rule).

Common denominator
A denominator that is a common multiple of all the denominators of a set of fractions, and which therefore enables their sums or differences to be found. A common denominator for 1/2 and 1/3 would be 6. hence both these fractions could be changed to sixths.

Common difference
The difference between any number and the next in an arithmetic progression.

Common factor
A number that will divide two or more other numbers without leaving a remainder. 3 is a common factor to 6 and 15.

Common logarithm
Another name for a logarithm to the base ten.

Common multiple
A number that is found in the multiplication tables of two or more given numbers. 15 is a common multiple of 3 and 5. 15 belongs in both the 3 and 5 timestables.

Commutative operation
An operation that is independent of the orders of the numbers or symbols concerned.
a + b = b + a
ab = ba

Compass
Instrument used for finding direction or bearing. Also, an instrument used for drawing circles or taking measurements, otherwise known as a pair of compasses.

Complement
The set of all the elements within the universal set that are not contained in a designated set.

Complementary angles
Two angles whose total is 90o.

Completing the square
Way of solving a quadratic equation by converting it into a perfect square i.e. put in the form (x + A) 2 = B, where A and B are constants.
For example solve x2 + 6x + 5 = 0
. Change to a perfect square by adding the square of half the coefficient of x (that is 32 = 9) to each half of the equation.
x2 + 6x = -5

x2 + 6x + 9 = -5 + 9

(x + 3) 2 = 4

x +3 = +/-2

x = -1 or û 5

These equations might also be solved by factorization.

Complex number
Number written in the form a + ib, where a and b are real numbers and i is the square root of -1. Some equations in algebra can not be solved without using complex numbers, because real numbers do not include square roots of negative numbers.

Component
One of the vectors produced when a single vector is resolved into two or more parts.

Computing device
Device built to carry out computations, for example the calculator or abacus.

Concave
Term used to describe a surface, meaning curving inwards or away from the eye. Concave is the opposite of convex.

Concentric circles
Two or more circles, sharing the same centre.

Concurrent lines
Two or more lines passing through a single point. The altitudes of any triangle pass through the same point and are therefore concurrent.

Cone
Solid figure with a two dimensional curve for a base, tapering to a point called the vertex. The line joining the vertex to the centre of the base is called the axis.

A cone that has its axis at right angles to the base is called a right cone.
A right circular cone of perpendicular height h and base of radius r has a volume, V = π r2h
The distance from the edge of the base to the vertex is called the slant height. The curved surface area of a right cone is πrl, where l is the slant height.

Congruent
The same size and shape.

Conical
Cone shaped.

Conic section
Curve that occurs when a conical surface is intersected by a plane. Different conic sections are obtained depending on where the plane intersects. An ellipse, parabola, and hyperbola are conic sections.

Conjugate angles
Two angles that add up to 360o.

Consecutive
Following on from each other in order, for example 6, 7, 8, are consecutive numbers.

Constant
A quantity that is fixed or does not change its value in relation to variables.

Construct
To draw accurately using the appropriate drawing instruments in geometry.

Construction
Line, angle or figure drawn to help solve a problem or produce a proof in geometry.

Continuous data
Data that can take an infinite number of values between whole numbers that cannot be measured completely accurately. Sizes of oranges on a tree would be continuous data where as the number of oranges would be discrete data.

Convergence
Property of a series of numbers in which the difference between consecutive terms gradually decreases.

Converse
Reversed order of a conditional statement. For example, the converse of the statement æif a, then bÆ is æif b, then aÆ.

Conversion graph
Graph used for changing values from one unit to another, such as currency.

Conversion table
Table used for changing values from one unit to another.

Convex
Term used to describe a surface, meaning curving outwards or towards the eye, like the outer surface of a ball.

Also used in geometry, to describe any polygon possessing no interior angle greater than 180o.

Coordinate
Number that defines the position of a point relative to a point or axis in geometry.

.
The coordinate here is 2 across and three up or (2, 3).

Coordinate geometry
Area of geometry in which lines, points, surfaces and shapes are represented by algebraic expressions. In plane coordinate geometry, the plane is usually defined by two axes at right angles to each other, the x-axis and the y-axis. A point on the plane can be represented by a pair of Cartesian coordinates, which define its position in terms of its distance along the x-axis and the y-axis.
.
Lines are represented as equations, and the graphs of varying equations can be drawn by plotting the coordinates of points that satisfy their equations, and joining up the points.

Coplanar
Used in geometry to describe points or lines that all lie in the same plane.

Correlation
Relation between two sets of information. They correlate when they vary together. This can be shown by plotting a best-fit line on a scatter graph. Also used in statistics, correlations are measured by the calculation of coefficients.

Correspondence
Relation between two sets where an operation on the members of one set maps some or all of them on to one or more members of the other.

Corresponding angles
Angles that are in matching positions on the same side of a transversal. Where the lines being cut by the transversal are parallel, the corresponding angles are equal. . With parallel lines we look for an æFÆ shape to find corresponding angles. Here x = y as they are corresponding angles.

Cosecant
Used in trigonometry, meaning a function of an angle in a right-angled triangle found by dividing the length of the hypotenuse by the length of the side opposite the angle.

Cosine
In trigonometry, a function of an angle in a right-angled triangle found by dividing the length of the side adjacent to the angle by the length of the hypotenuse. Usually shortened to cos.

Cosine rule
Rule of trigonometry that relates the sides and angles of triangles.

Cotangent
In trigonometry, the function of an angle in a right-angled triangle. This is calculated by dividing the length of the side adjacent to the angle by the length of the side opposite it.

Critical path analysis
Used to manage complex projects to minimize the amount of time taken, this procedure shows which subprojects can run simultaneously, and which subprojects have to be completed before others can follow on. A planning schedule may be produced to show when each subproject should start and finish in order to complete the whole project most efficiently.

Cross multiply
In the case of two fractions, to multiply the numerator of one by the denominator of the other and vice versa.

Cross section
Surface made when a solid is cut through by a plane at right angles to its axis.

Cryptarithm
A number puzzle in which an indicated arithmetical operation has some or all of its digits replaced by letters or symbols and where the restoration of the original digits is required. Each letter represents a unique digit.

Cube
Solid figure made up of six faces. These faces are all squares and of equal area.

Cube
To multiply a number by itself and then by itself again. For example, 3 cubed = 33 = 3 x 3 x 3 = 27.

Cubic centimetre (or metre)
Metric measure of volume, corresponding to the volume of a cube whose edges are all 1 cm (or 1 metre) in length. cm3

Cubic equation
Equation in which the largest power of x is 3. E.g. y = 5x3, y = x3 - 2x2.

Cuboid
Three-dimensional six-sided prism whose faces are all rectangles.

Cumulative frequency
In statistics, the total frequency of a given value up to and including a certain point in a set of data. Used to draw the cumulative frequency curve.

Curve
In geometry, the locus of a point moving according to specified conditions.

Cusp
Point where two branches of a curve meet and the tangents to each branch coincide.

Cyclic
Term used in geometry to describe a polygon of which each corner lies on the circumference of a circle.

Cyclic patterns
Patterns in which simple ideas are repeated to form more complex designs.

Cyclic polygon
A polygon whose vertices lie on a circle.

Quadrilateral with all four of its vertices lying on the circumference of a circle. Its properties are.

Cycloid
In geometry, a curve that resembles a series of arches traced out by a point on the circumference of a circle that rolls along a straight line.

Cylinder
A tubular solid figure with a circular base.

The volume V of a cylinder is give by
V = πr2h
The total surface area, A, of a cylinder is given by
A = 2πr(h + r).
2πrh is the curved surface area and 2πr2 is the area of both the end circles.

Cylindrical
Having the shape of a cylinder.

Century
One Hundred Years

Closed Curve
A continuous curved line that has the same start and end points, i.e. it is joined.

Calendar
A table that shows a year broken down into months, weeks and days.

One of the temperature systems used in the metric system.
0c - Freezing point
100c - Boiling Point
37v - Human Body Temperature.

Census
The collection of data from the whole population of a country.

Cluster
Numbers that center around a particular point in a set of numbers. A cluster is easilly identified in a Scattergram.

Composite
A number with more than two factors.

Convergent
A series of items that are heading towards the same point. For example, several lines that are all leading towards the same point. Another example is the following series of numbers:
9, 8, 7, 6, 5, 4, 3, 2.
These numbers are said to be converging to zero.

Convex Polygon
A polygon (with all interior angles) of which every interior angle is less than 180 degrees

Words beginning with the letter D

Data
Term used to describe raw facts, figures and symbols, that have may not been processed.

Database
Organised collection of data.

Decagon
Polygon with ten sides.

Decimal
Number less than 1, expressed by figures written after the decimal point.

Decimal fraction
Fraction expressed by the use of the decimal point, that is, a fraction in which the denominator is any higher power of 10. 7/10 is normally expressed as 0.7 and 37/100 would be shown as 0.37. Not all fractions can be expressed exactly as a decimal fraction.

Decimal number system
Also know as the denary number system. This is the most commonly used number system, to the base ten.

Decimal point
Dot dividing a decimal numberÆs whole part from its fractional part.

Definition
Statement which describes a mathematical object.

Deficient number
A positive integer that is larger than the sum of its proper divisors.

Degree
Unit of measurement of an angle or arc (symbol o). Temperature is also measured in degrees which are divided on a decimal scale.

Denominator
The bottom number of a fraction. 2/3 Here the 3 is the denominator.

Density
Measure of the compactness of a substance, equal to its mass per unit volume, measured in kg per cubic metre. The density D of a mass m occupying a volume V is given by the formula D = m/V.

Depression
The angle of depression is an downwards angle made with the horizontal.

Depth
Distance from the top downwards or from front to back.

Derivative
Limit of the gradient of a chord linking two points on a curve as the distance between the points tends to zero. Also called the differential coefficient.

Determinant
Array of elements written as a square, denoted by two vertical lines enclosing the array. Determinants are used to solve sets of simultaneous equations by matrix methods.

Diagonal
Straight line joining one vertex to another (but not one next to it) on a polygon.

Diameter
Straight line dividing a circle into two equal halves. All diameters pass through the centre of the circle.

Difference
Result obtained when subtracting one number from another.

Differences
Set of numbers obtained from a sequence by subtracting each element from its successor.

Differential calculus
That part of calculus that deals with the operation of differentiation of functions.

Digit
Any of the numbers from 0 to 9 in the decimal system.

Digimetic
A cryptarithm in which digits represent other digits.

Digital root
Digit formed by adding the digits of a number. If this leads to a total of 10 or more, the resultant digits are added.

Dihedral angle
The angle formed by two planes meeting in space.

Dimension
In geometry, the number of measures needed to specify the size of a figure.

Directed number
Whole number with a positive or negative sign attached. Numbers could be written as +5, -7, +2, -8.

Discrete data
Data that take only whole number or fractional values. The number of oranges on a tree would be discrete data.

Dispersion
In statistics, the extent to which data are spread around a central point.

Displacement
Movement from one point to another.

Displacement vector
Vector which describes how an object has been moved from one position to another.

Distance-time graph
Graph used to show the motion of a body by illustrating the relationship between the distance that it travels and the time taken.

Distribution
In statistics, the pattern of frequency for a set of data.

Distributive operation
An operation, such as multiplication, that bears a relationship to another operation, such as addition, such that
a x (b + c) = (a x b) + (a x c).

Dividend
Any number that is to be divided by another number

Division
Basic operation of arithmetic.

Divisor
Any number that is to be divided into another number.

Dodecagon
A polygon with 12 sides.

Dodecahedron
A solid figure with 12 faces A regular dodecahedron is a regular polyhedron with 12 faces. Each face is a regular pentagon.

Domain
Base set of numbers on which a function works, mapping it onto a second set.

Domino
Two congruent squares joined along an edge.

Duodecimal system
System of arithmetic notation using twelve as a base.

Decomposition
A method of subtraction where you carry or borrow tens, hundreds, etc. because you are unable to subtract a large number from a smaller one.

Deca- (or Deka-)
The prefix meaning ten

A period of ten years.

Decahedron
A Polyhedron with ten faces

Deduct
To subtract

Decrease
When something gets smaller in size

Direction
The direction in which something is going/moving

Descending
Arranged from largest to smallest

Dozen
A group of 12 items.
A Bakers Dozen is a group of 13 items.

Double
To multiply something by .two
For example, double six is 6 x 2 = 12

Distance
The length between two objects/points

Dot Plot
A number line that is long enough to cover all the opssible results in a sample. A dot is placecd over the number which represents a result from the sample. If two or more dots land in the same place, they are stacked on top of each other, not just overlapped.

Diamond
A plane shape with no right anges and four equal sides

Dice (or die)
A cube marked with dots or numbers, usually from one to six

Words beginning with the letter E

Eccentricity
In geometry, this is the distance of any point on a curve of a conic section from a fixed point (the focus) divided by the distance of that point from a fixed line (the directrix).

Econometrics
Use of maths within economics to analyse economic data using statistics.

Edge
Line along which two planes of a solid figure meet. May also refer to a line joining two nodes or vertices on a graph.

Egyptian fraction
A number of the form where x is an integer is called an Egyptian fraction.

Element
Member of a set.

Elevation
A scale drawing of one side of a building or object. The angle of elevation is an upward angle made with the horizontal.

Ellipse
Curve joining all points (loci) around two fixed points (foci) so that the sum of the distances from those two points is always constant.

Empty set
Set with no elements. Symbol Ï or { }.

Enlargement
Transformation that produces a figure of a different size, but with similar dimensions to the original. May be smaller or larger than the original.

Enumerable set
A countable set.

Envelope
In geometry, a curve that touches all the members of a family of curves or lines.

Epicycloid
In geometry, a curve that resembles a series of arches traced out by a point on the circumference of a circle that rolls around another circle of a different diameter.

Equation
Expression representing the equality of two expressions involving constants and/or variables, and usually including an equals sign.

Equiangular polygon
A polygon all of whose interior angles are equal.

Equichordal point
Point inside a closed convex curve in the plane is called an equichordal point if all chords through that point have the same length.

Equilateral
Having all sides of equal length, referring to a geometrical figure.

Equivalent
Having the same value but a different appearance.

EratosthenesÆ Seive
Method for finding prime numbers, involving writing in sequence all the numbers from 2. Then, starting with 2, cross out every second number (but not 2 itself), thus eliminating numbers that can be divided by 2. Next, starting with 3, cross out every third number, (but not 3 itself), and continue the process for 5, 7, 11, and so on. The numbers that remain are primes.

Error
Amount by which an incorrect answer differs from the correct one.

Escribed circle
An escribed circle of a triangle is a circle tangent to one side of the triangle and to the extensions of the other sides.

Estimate
To perform a rough calculation.

Euler line
The Euler line of a triangle is the line connecting the centroid and the circumcenter.

Evaluate
To find the value of.

Even function
A function f(x) is called an even function if f(x)=f(-x) for all x.

Even number
Any number divisible by 2.

Event
In statistics, any occurrence to which a probability can be attached.

Exceed
To be more than.

Exception
Something that is not subject to a general rule.

Excentre
The centre of an excircle.

Excircle
An escribed circle of a triangle.

Exclusive
Description of events which cannot happen at the same time.

Expand
In algebra, to multiply out.

Expectation
In statistics, the numerical probability of a certain result.

Exponent
A number that shows the number of times a term is multiplied by itself. May also be called the index or power.

Exponential
Descriptive of a function in which the variable quantity is an exponent.

Exponential function
The function f(x)=e.

Expoential function to base a
The function f(x)=a.

Expression
Mathematical phrase written in symbols.

An exradius of a triangle is the radius of an escribed circle.

Extend
To continue a line, usually in order to deduce some property of a figure.

Exterior angle
One of the four external angles formed when a straight line or tranversal cuts through a pair of lines, usually parallel.

w, x y and z are all exterior angles.

Exterior angle
Angle formed by extending a side of a polygon.

e (or E)
Exponent or index.
The number that another number is raised to, e.g. 23 means two raised to the power three - i.e. two multiplied by itself three times.
The answer to this is obtained as follows:
2 x 2 x 2 = 8

Equal (or equals)
To have the same amount or value, for example:
2 + 3 = 5 is the same as:
2 + 3 is the same value as 5.

Equality
The state of being equal

End Point
The point that marks the end of a line or a line segment, i.e. where you measure from and to when measuring the length of a line

Equate
Make (or treat as) equal

Words beginning with the letter F

Face
Term used in geometry referring to a plane surface of a solid enclosed by edges. A cube has six square faces.

Factor
Number that divides into another number exactly.

Factorization
The writing of a number or of a polynomial as the product of some of its factors. Factorization may be used to solve quadratic equations.
(x + 1)(x û 3) = x2 - 2x û 3. Therefore factors of x2 - 2x û 3 are x + 1 and x û 3.

Factorial
In reference to a positive number, the factorial is the product of all the integers inclusive between 1 and the number itself. It is indicated by the symbol æ!Æ.
E.g. 5! = 5 x 4 x 3 x 2 x 1

Farenheit scale
Temperature scale used in English-speaking countries up until the 1970s, to be replaced by the Celsius scale.
To change between Farenheit and Celcius we can use
F = 9/5C + 32

Farey sequence
The sequence obtained by arranging in numerical order all the proper fractions having denominators not greater than a given integer.

Fathom
Unit of depth measurement used before metrication.

Fibonacci numbers
Sequence in which each number is the sum of its two predecessors. 0, 1, 1, 2, 3, 5,...

Figurate numbers
Polygonal numbers.

Finite
Opposite of infinite, meaning having a countable number of elements.

Finite group
A group containing a finite number of elements.

Flow chart
Diagram showing the steps that must be followed to solve a particular problem. The steps are enclosed by boxes and are linked by arrows.

Focal chord
A chord of a conic that passes through a focus.

A line segment from the focus of an ellipse to a point on the perimeter of the ellipse.

Foot
Imperial unit of length, equivalent to 0.3048 m, containing 12 inches.

Foot
The point where a line meets a second line to which it is perpendicular.

Formula
Set of symbols and numbers which expresses a mathematical factor rule.

Fourier series
A periodic function with period 2π.

Fractal
Irregular surface or shape resulting from repeated subdivision.

Fraction
Number that indicates one or more equal parts of a whole. Usually, the number of equal parts into which the number is divided (denominator) is written below a horizontal line, and the number of parts comprising the fraction (numerator) is written above.
E.g.

Frequency
Number of times an event occurs The set of frequency data is called a frequency distribution and is usually presented in a frequency table or shown diagramatically as a frequency polygon.

Frustum
In geometry, a æsliceÆ taken out of a solid figure by a pair of parallel planes.

Function
Rule that maps each element in a given set (the domain) onto just one element in another set (the range). Functions are used in all branches of mathematics, physics generally. An inverse function maps each element in the range back onto the original element in the domain. A composite function is made up of two or more simple functions.

Words beginning with the letter G

Gallon
Imperial liquid or dry measure, equivalent to 4.456 litres.

Generalize
To extend a number of results to form a rule.

Generate
To produce a sequence of numbers from either the relationship between one number and the next or the relationship between a member of the sequence and its position. In geometry, shapes are generated by moving lines.

Geoboard
A flat board into which nails have been driven in a regular rectangular pattern. These nails represent the lattice points in the plane.

Geodesic
The arc on the EarthÆs surface of shortest length joining two given points.

Geodesy
A branch of mathematics dealing with the shape, size, and curvature of the Earth.

Geometric mean
The nth root of the product of n positive numbers. The geometric mean is always less than the arithmetic mean.

Geometric progression
Sequence of terms in which each term is a constant multiple of the one preceding it.

Geometric series
A series in which the ratio of each term to the preceding term is a given constant.

Geometry
Area of mathematics concerned with the properties of space, usually in terms of plan and solid figures.

Gergonne point
In a triangle, the lines from the vertices to the points of contact of the opposite sides with the inscribed circle meet in a point called the Gergonne point.

Gnomon magic square
A 3 X 3 array in which the elements in each 2 X 2 corner have the same sum.

Golden rectangle
A rectangle whose sides are in the golden ratio.

The slope of a straight or curved line on a graph. Gradient is a measure of rate of change and can be used to represent such quantities as velocity and acceleration.

Gram
One-thousandth of a kilogram, measurement of mass. Symbol g.
1000 g = 1 Kg
1 gram can be split into 1000 milligrams
1000 mg = 1 g

Graph
Pictorial representation of numerical data, or method of showing the mathematical relationship between two or more variables by drawing a diagram.

Graphical methods
Ways of solving problems and equations by finding the points of intersection of curves and lines on graphs.

Gravity
The natural force with which masses are drawn together. The acceleration due to gravity on Earth is 9.8 m/s2.

Great circle
Circle drawn on a sphere such that the diameter of the circle is the diameter of the sphere.

Greatest common divisor
The greatest common divisor of a sequence of integers, is the largest integer that divides each of them exactly.

Greatest common factor
Same as greatest common divisor.

Grid
A network of crossing parallel lines.

Group
Finite or infinite set of elements that can be combined by an operation.

Growth and decay curve
Graph that shows exponential change as occurs with compound interest and populations.

Words beginning with the letter H

Half
One of two equal parts of a whole unit.

Half-turn
A transformation in which a figure is rotated through 180o.

Halve
To divide into two equal parts.

Hankel matrix
A matrix in which all the elements are the same along any diagonal that slopes from northeast to southwest.

Harmonic analysis
The study of the representation of functions by means of linear operations on characteristic sets of functions.

Harmonic division
A line segment is divided harmonically by two points when it is divided externally and internally into he same ratio.

Harmonic mean
The harmonic mean of two numbers a and b is 2ab/(a + b) .

Hectare
Metric unit of area equal to 10,000 square metres (approximately 2.47 acres), symbol ha.

Height
Distance from the top to the base of a plane figure or solid.

Helix
A three-dimensional curve that looks like a corkscrew, spring or screw thread. The parameteric equation for a helix is x=a cos t, y=a sin t, z=bt

Hemisphere
Half a sphere, produced by slicing a sphere along a great circle.

Heptagon
A seven-sided polygon.

Hexagon
A six-sided polygon.

Hexagonal number
A number of the form n(2n-1) .

Hexagonal prism
A prism with a hexagonal base.

Hexahedron
A polyhedron having 6 faces. The cube is a regular hexahedron.

Hexomino
A six-square polyomino.

Heronian triangle
A triangle with integer sides and integer area.

Highest common factor
The highest number in a set of numbers that will divide every member of the set without leaving a remainder.

Histogram
Graph used in statistics to show frequency of data, in which the horizontal axis details discrete units or class boundaries, and the vertical axis represents the frequency. Blocks are drawn so that their areas are proportional to the frequencies within a class or across several class boundaries.

Horizontal
Flat and level, having the same direction as the horizon

Hour
Period of time comprising 60 minutes.

Hyperbola
In geometry, a curve formed by cutting a right circular cone with a plane so that the angle between the plane and the base is greater than the angle between the base and the side of the cone. It is also the graph formed by two variables that are related in such a way that one increases as the other decreases.

Hypocycloid
In geometry, a cusped curve traced by a point on the circumference of a circle that rolls around the inside of a larger circle.

Hypotenuse
The longest side of a right-angled triangle, opposite the right angle.

Hypothesis
An unproven idea used in problem solving.

Words beginning with the letter I

Icosahedron
Twenty-sided polyhedron.

Identity
An operation or number that leaves others unchanged when combined with them.

Image
Point or number resulting from a mapping or transformation.

Imply

Improper fraction
Fraction whose numerator is larger than its denominator.
E.g.

Incentre
The incentre of a triangle is the centre of its inscribed circle.

Incircle
The circle inscribed in a given figure.

Inch
Imperial unit of linear measure, a twelfth of a foot.

Independent variable
Variable that does not depend on another variable for its values.

Index
Numerical scale used in statistics to summarise a number of changes and by means of which different levels of data can be compared.

Index
Another term for exponent. Here 63, 3 is the index number.

Inequality
Statement that one quantity is larger or smaller than another, using the symbols < and >.

Infinity
Mathematical quantity that is larger than any fixed assignable quantity. Symbol ?

Inflection
A point of inflection of a plane curve is a point where the curve has a stationary tangent, at which the tangent is changing from rotating in one direction to rotating in the opposite direction.

Inscribed circle
Circle drawn inside a plane figure which touches all the sides of the figure.

Integer
Any positive or negative whole number, -3, -2, -1, 0, 1, 2, 3, ...

Intercept
Point at which a line or curve cuts across a given axis.

Intercept
The segment cut out of a transversal by the pair of lines that it cuts across.

Interior angle
One of the four internal angles formed when a transversal cuts two or more (usually parallel) lines.

Interior angle
One of the angles inside a polygon.

Interpolation
Estimate of a value lying between two known values.

Interquartile range
In statistics, a measure of dispersion in a frequency distribution, equalling the difference in value between the upper and lower quartiles. It could be described as the middle half.

Intersection
Point where two lines or curves meet on a graph, providing the graphical solutions of equations.

Intersection
In set theory, the set of elements that belong to both set A and set B.

Interval
The difference between the smallest and largest measurement in a single set in statistics.

Inverse
The partner of an element that produces the identity when combined with the element.

Inverse function
A function that exactly reverses the transformation produced by a function. The inverse function of x is .

Invert
To turn upside down.

Investigation
Detailed study of a mathematical situation.

Involute
Spiral that can be thought of as being traced by a point at the end of a taut non-elastic thread being wound on to or unwound from a spool.

Irrational number
Number that can not be expressed as an exact fraction i.e. in the form , where a and b are integers.

Isogonal conjugate
Isogonal lines of a triangle are cevians that are symmetric with respect to the angle bisector. Two points are isogonal conjugates if the corresponding lines to the vertices are isogonal.

Isometric paper
Paper ruled with an isometric grid, used for making two-dimensional drawings of three-dimensional objects where lengths are preserved.

Isometric transformation
Transformation in which length is preserved.

Isosceles triangle
Triangle with two equal sides.

Isosceles tetrahedron
A tetrahedron in which each pair of opposite sides have the same length.

Isosceles trapezoid
A trapezium in which the two non-parallel sides have the same length.

Isotomic conjugate
Two points on the side of a triangle are isotomic if they are equidistant from the midpoint of that side. Two points inside a triangle are isotomic conjugates if the corresponding cevians through these points meet the opposite sides in isotomic points.

Iteration
Method of solving equations by a series of approximations which approach the exact solution more and more closely.

Words beginning with the letter J

Joint probability function
A function that gives the probability that each of two or more random variables takes at a particular value.

Joint variation
A variation in which the values of one variable depend upon those of 2 or more variables .

Jordan curve
A simple closed curve.

Jordan matrix
A matrix whose diagonal elements are all equal (and nonzero) and whose elements above the principal diagonal are equal to 1, but all other elements are 0.

Joule
A unit of energy or work.

Jump discontinuity
A discontinuity in a function where the left and right-hand limits exist but are not equal to each other.

Jump Strategy
To jump along a number line in tens and ones to somplete a large calculation, for example, the following calculation could be completed using the jump strategy:
27 + 76.

Words beginning with the letter K

Kilo-
Prefix meaning multiplication by 1,000.

Kilogram
Unit of mass, symbol kg.

Kilometre
Unit of length, symbol km.

Kinematics
A branch of mechanics dealing with the motion of rigid bodies without reference to their masses or the forces acting on the bodies.

Kite
Quadrilateral with two pairs of adjacent equal sides and one axis of symmetry.

Knot
Unit of shipÆs speed, equal to one nautical mile per hour.

Knot
A curve in space formed by interlacing a piece of string and then joining the ends together.

Konigsberg bridge problem
Puzzle that led to the development of topology.

Kilo-Litre (KL)
Standard metric unit for measuring liquids. The equivalent of 1000 Litres (L)

km/h
A measure of speed. Means Kilometers per hour.

Words beginning with the letter L

L-tetromino
A tetromino in the shape of the letter L.

Latin square
An n x n array of numbers in which only n numbers appear. No number appears more than once in any row or column.

Latitude and longitude
Imaginary lines used to indicate position on the globe. Lines of latitude are drawn parallel to the equator, and lines of longitude are drawn at right angles to these.

Lattice
A network of straight lines.

Lattice points
The points of intersection of the lines in a lattice.

Latus rectum
A chord of an ellipse passing through a focus and perpendicular to the major axis of the ellipse. Plural: latera recta.

Least common multiple
The least common multiple of a set of integers is the smallest integer that is an exact multiple of every number in the set.

Length
A measure of the length of an object from end to end.

Limit
In an infinite sequence, the final value towards which the sequence is tending.

Linear equation
An equation involving two variables (x,y) of the general form y = mx + b where m is the slope of the line represented by the equation and b is the y intercept, or the value of y where the line crosses the y axis in the Cartesian coordinate system.

Linear programming
In mathematics or economics, a set of techniques for finding the maxima or minima of certain variables governed by linear equations or inequalities.

Line of best fit
On a scatter diagram, line drawn as near as possible to the various points so as best to represent the trend being graphed.

Line segment
The part of a line between two given distinct points on that line (including the two points) .

Litre
Metric unit of volume, equal to one cubic decimetre. One litre is approximately equal to 1.76 pints.

Locus
Path traced out by a moving point. The locus of a point that moves so it is always at the same distance from another fixed point is a circle; the locus of a point that is always at the same distance from two fixed points is a straight line that perpendicularly bisects the line joining them.

Logarithm
The exponent or index of a number, usually to the base 10. Abbreviated to log.

Logic
The study of the formal laws of reasoning.

Loop
The part of a curve which encloses a space when the curve crosses itself. In a flow chart, a path which keeps on returning to the same point.

Lower bound
The value that is less than or equal to all of the values of a given set.

Lowest common denominator
The smallest number that is a multiple of each of the denominators of a set of fractions.

Lowest common multiple
The smallest number that is a multiple of all the numbers in a given set. The lowest common multiple of 6, 8 and 15 is 120.

Loxodrome
On a sphere, a curve that cuts all parallels under the same angle.

Lune
The portion of a sphere between two great semicircles having common endpoints (including the semicircles) .

Leap Year
A year that has 366 days instead of 365. This occurs every four years.

Least
The smallest of a group

Line Graph
A graph that uses lines to join points that represent data

Line Symmetry
An object (shape) has line symmetry if it can be divided in half by one or more lines (axis) of symmetry

Words beginning with the letter M

Macro-
Prefix meaning on a very large scale.

Magic square
Square formed by numbers in which the rows, columns and diagonals add up to the same total.

Magnititude
Size irrespective of sign.

Major arc
The larger of the two arcs formed when a circle is divided into two unequal parts by a straight line or chord.

Major axis
The major axis of an ellipse is it's longest chord.

Majority
The greater number or part of a set.

Mantissa
The decimal part of a logarithm.

Mapping
A rule that links elements from one set with those of another.

Mass
The amount of matter in a body. It determines the acceleration produced in a body by a given force acting on it , as well as the force exerted on a body by gravity on Earth.

Mathematical induction
Formal method of proof in which the proposition P(n + 1) is proved true on the hypothesis that the proposition P(n) is true.

Matrix
A square or rectangular array of numbers or algebraic variables. Matrices can be used for, among other things, solving simultaneous linear equations and transformations.

Maximum and minimum
In coordinate geometry, points at which the slope of a curve representing a function changes from positive to negative (maximum), or from negative to positive (minimum).

Mean
The average of a number of terms or quantities.
The simple arithmetic mean is the average value of the quantities, i.e. the sum of the quantities divided by their number.
The weighted mean takes into account the frequency of the terms that are summed, i.e. it is calculated by multiplying each term by the number of times it occurs, summing the results and dividing this total by the total number of occurrences.
The geometric mean of n quantities is the nth root of their product. In statistics, it is a measure of central teneancy of a set of data.

Mean deviation
In statistics, a measure of the spread of a population from the mean.

Medial triangle
The triangle whose vertices are the midpoints of the sides of a given triangle.

Median
The middle number of an ordered group of numbers. If there is no middle number, the median is the mean of the two middle numbers.

Median
In geometry, a line form the vertex of a triangle to the mid-point of the opposite side.

Mega-
Prefix indicating multiplication by a million.

Member
One of the elements belonging to a set.

Mensuration
The science of measurement.

Mersenne number
A number of the form 2 - 1 where p is a prime.

Mersenne prime
A Mersenne number that is prime.

Metre
SI unit of length, symbol m. It is defined by scientists as the length of the path travelled by light in a vacuum during the time interval of 1/299 792 458 of a second.

Micro-
Prefix denoting a one-millionth part or 10-6.

Midpoint
The point M is the midpoint of line segment AB if AM=MB. That is, M is halfway between A and B.

Mile
Imperial unit of length. 1 mile is approximately 1.60934 km.

Milli-
Prefix denoting a one-thousandth part.

Million
One thousand thousands, 1,000,000 or 106.

Minor arc
The smaller of the two arcs formed when a circle is divided into two unequal parts by a straight line or chord.

Minor axis
The minor axis of an ellipse is its smallest chord.

Minus sign
The sign indicating subtraction or denoting a negative number. Symbol - .

Minute
Basic unit of time. There are 60 minutes in one hour and 60 seconds in one minute.

Minute or arc minute
Of an angle, a unit equal to one-sixtieth of a degree. Symbol æ

Mixed number
A number consisting of both whole and fractional parts. E.g. 4 1/2.

Mobius strip
Structure made by giving a half twist to a flat strip of paper and joining the ends together. If cut down the centre of the strip, instead of two new strips of paper, only one long strip is produced.

Mode
The element that appears most frequently in a given group.

Modulus
Another name for absolute value.

Monomial
An algebraic expression consisting of just one term.

Monotone
A sequence is monotone if its terms are increasing or decreasing.

Monic polynomial
A polynomial in which the coefficient of the term of highest degree is 1.

Monochromatic triangle
A triangle whose vertices are all coloured the same.

Multinomial
An algebraic expression consisting of 2 or more terms.

Multiple
Any number that is the product of a given number. For example, 15 is a multiple of 3 since it appears in the multiplication table of 3.

Multiplication
One of the four basic operations of arithmetic, usually written in the form a x b or ab.

Multiplication table
The set of multiples of a given number obtained by multiplying it by 1, 2, 3 etc.

Mutually exclusive
Description of two events that can not happen together. It is not possible to throw Heads and Tails on the same coin at the same time.

Maximum
Highest or greatest amount or value

Measure
The use of standard units to find out the size or quantity of something in regard to the following:
1) Length
3) Height
4) Area
5) Mass
6) Weight
7) Volume
8) Capacity
8) Temperature
9) Time

Metric System
The decimal system of measurement, which uses multiples of 10

MilliLitre (ml)
Standard metric unit for measuring capacity.
1000ml = 1l

MilliMetre (mm)
A standard metric unit for measuring length.
10mm = 1cm
1000mm = 1m

Minimum
Lowest or least amount or value

Month
Approximatley the time it takes for the moon to orbit earth.
There are 12 months in a year

MPG
Miles Per Gallon
A measurement of fuel consumption.
This measurement vares depending on vehicle, engine, driving habits and road condition

MPH
Miles Per Hour
Measurement of speed - measure the number of miles travelled per hour.

Words beginning with the letter N

The point on the celestial sphere in the direction downwards of the plumb-line.

Nagel point
In a triangle, the lines from the vertices to the points of contact of the opposite sides with the excircles to those sides meet in a point called the Nagel point.

Natural number
One of the set of numbers used for counting.

Negative integer or number
Any real number with a value of less than zero. Every positive number has its negative partner, their sum being zero.

Net
In geometry, a plan which may be used to make a model of a solid. Below is one net for a cube.

Network
System of nodes (junctions) and arcs (transport routes) through which goods, services, people, money or information flow.

Nine point centre
In a triangle, the circumcentre of the medial triangle is called the nine point centre.

Nine point circle
In a triangle, the circle that passes through the midpoints of the sides is called the nine point circle.

Node
Point where routes meet.

Nonagon
A 9 sided polygon.

Nonagonal number
A number of the form n(7n-5)/2.

Nonary
Associated with 9.

Normal distribution curve
The bell-shaped curve obtained when continuous variation within a population is expressed graphically.

Null hypothesis
The null hypothesis is the hypothesis that is being tested in a hypothesis-testing situation.

Null set
The empty set.

Number line
A line on which each point represents a real number.

Numerical analysis
The study of methods for approximation of solutions of various classes of mathematical problems including error analysis.

Number
Symbol used in counting or measuring. There are various kinds of numbers.

Numerator
The top number of a fraction.

Number theory
The study of integers.

Numeral
A symbol used to represent a number, an example of this is the way Roman Numerals are displayed, for axample:
1 = I
2 = II
3 = III etc.

Words beginning with the letter O

Oblate spheroid
An ellipsoid produced by rotating an ellipse through 360o about its minor axis.

Oblique angle
An angle that is not 90o.

Oblique coordinates
A coordinate system in which the axes are not perpendicular.

Oblique triangle
A triangle that is not a right triangle.

Observation sheet
In statistics, specially prepared record sheet for experiments, including space for tally marks and for total frequency.

Obtuse angle
An angle greater than 90o but less than 180o.

Octagon
Eight-sided polygon.

Octahedron
A solid comprising of 8 faces. A regular Octahedron has eight faces, each of which is a equilateral triangle.

Octant
Any one of the 8 portions of space determined by the 3 coordinate planes.

Odd
Describing any number not divisible by 2.

Odd function
A function f(x) is called an odd function if f(x)=-f(-x) for all x.

Ogive
In statistics, the curve on a graph representing cumulative frequency.

Open interval
An interval that does not include its two endpoints.

Operation
Action on numbers, matrices, or vectors that combines them to form others. The basic operations on numbers are addition, subtraction, multiplication, and division.

Opposite side
In a right-angled triangle, the side opposite a given angle, but not the hypotenuse.

Orbit
The path that one heavenly body follows around another, or the path of a satellite travelling around the Earth.

Order
To arrange with regard to size or quantity or other quality.

Ordered pair
A pair of numbers whose order make a difference to their meaning.

Ordinal number
One of the series first, second, third, fourthà. Ordinal numbers relate to order rather than quantity. Cardinal number relate to quantity rather than order.

Ordinate
In coordinate geometry, the y-coordinate of a point. The distance from the y-axis. The coordinate (2, 3) will have an ordinate 3.

Origin
The point where the x axis meets the y axis, (0, 0).

OR rule
Rule used for the finding the combined probability of one event or another taking place.
If a blue die and a red die are thrown together, the probability of a blue 6 is 1/6 and the probability of a red 6 is 1/6. Therefore the probability of throwing a blue six OR a red six is
1/6 + 1/6 = 2/6 = 1/3

Orthic triangle
The triangle whose vertices are the feet of the altitudes of a given triangle.

Orthocentre
The point of intersection of the altitudes of a triangle.

Ounce
Imperial measure of weight, symbol oz. One ounce approximately equals 28.35 grams. There are 16 ounces in one pound.

Outcome
In probability theory or statistics, one possible result of an experiment.

Oval
Egg shaped.

Oblong
- Four right angles,
- Two pairs of equal parallel lines, each pair being a different length

Order of Operation
The order in which the operations in an equation shoud be done

Order of Rotational Symmetry
The number of times the outline of a rotating shape matches the turning shape. For example, an equalatiral triangle has an order of three, and a square has an order of four.

Ordinal
A number that shows place or position, for example, to donote the position you come in a race - 1st, 2nd, 3rd, etc.

Outlier
A value in a set that is far away from most of the other valuse in the set.

Words beginning with the letter P

Palindrome
A positive integer whose digits read the same forward and backwards. For example 2235322.

Palindromic
A positive integer is said to be palindromic with respect to a base b if its representation in base b reads the same from left to right as from right to left.

Pandiagonal magic square
A magic square in which all the broken diagonals as well as the main diagonals add up to the magic constant.

Pandigital
A decimal integer is called pandigital if it contains each of the digits from 0 to 9.

Parabola
A curve formed by cutting a right circular cone with a plane parallel to the sloping side of the curve. It can be also defined as a path traced out by a point that moves in such a way that the distance from a fixed point is equal to its distance from a fixed straight line.

Parallel lines and planes
Straight lines or planes that always remain a constant distance from one another no matter how far they are extended.

Parallelogram
A quadrilateral with opposite pairs of sides equal in length and parallel, and opposite angles equal. When all four sides are equal in length, the parallelogram is called a rhombus.

Paraboloid
A paraboloid of revolution is a surface of revolution produced by rotating a parabola about its axis.

Parallelepiped
A prism whose bases are parallelograms.

Parameter
Variable factor or characteristic, such as the length or height of a rectangle.

Pascal's Triangle
A triangular formation of numbers, with 1 at the apex, in which each number is the sum of the pair of numbers above it.

Pattern
A regular design comprising shapes or numbers.

Pentagon
A five-sided plane figure.

Pentagonal number
A number of the form n(3n-1)/2.

Pentomino
A five-square polyomino.

Percentage
Way of representing a number as a fraction of 100. Thus 45 percent (45%) equals 45/100, and
45% of 20 = 45/100 x 20 = 9.

Percentile
In a frequency distribution, one of the 99 values of a variable that divide its distribution into 100 pars of equal frequency. In practice, only certain of the percentiles are used. The median (the 50th percentile, the lower and upper quatiles (the 25th and 75th percentiles). Other used are the 10th and 90th percentiles which cut off the bottom and top 10% of the frequency distribution, and the 5th and 95th percentiles.

Perfect cube
An integer is a perfect cube if it is of the form m3 where m is an integer.

Perfect number
A positive integer that is equal to the sum of its proper divisors. For example, 28 is perfect because 28=1+2+4+7+14.

Perfect power
An integer is a perfect power if it is of the form m where m and n are integers and n>1.

Perfect square
An integer is a perfect square if it is of the form m2 where m is an integer.

Perimeter or boundary
A line drawn around the edge of an area or shape, and also the length of that line. The perimeter of a circle is known as its circumference.

Permutation
Aspecified arrangement of a group of objects.

Perpendicular
At a right angle. Also, a line at right angles to another or to a plane.

Perpendicular bisector
A straight line perpendicular to a line segment and passing through its mid-point.

Perspective
The realistic representation of a three-dimensional object in two dimensions.

Pi
Symbol π, the ratio of the circumference of a circle to its diameter. The value of pi is 3.1415926, correct to seven decimal places. Common approximations to π are and 3.14.

Pictogram
A pictorial way of presenting statistical data, in which a symbol is used to represent a specific quantity of items.

Pie chart
Method of displaying proportional information by dividing a circle into different sized sectors. The angle of each sector is proportional to the size, expressed as a percentage, of the group of data that it represents.

Place value
The value given to a digit because of its position within a number.

Plan
A scale drawing of an object viewed from above.

Plane
A flat surface.

Plane figure
In geometry, a two-dimensional figure.

Plot
To mark the points corresponding to the number pairs of a function on a graph.

Point
In geometry, a basic element, whose position in the Cartesian system may be determined by coordinates.

Polar coordinates
A way of defining the position of a point in terms of its distance from a fixed point and its angle degrees or radians to a fixed line or axis.

If the distance from the origin to Q is 6 units, then the polar coordinate of Q would be described as (6, 30o).

Polygon
In geometry, a plane figure with three or more straight lines.

Polyhedron
In geometry, a solid figure with four or more plane faces.

Polynomial
An algebraic expression that has one or more variables, denoted by letters.

Polyomino
A planar figure consisting of congruent squares joined edge-to-edge.

Population
In statistics, the universal set from which a sample of data is selected.

Position vector
A vector that defines the position of a point.

Positive
Greater than zero.

Positive integer
Any whole number from 0 upwards.

Pound
Imperial unit of weight, symbol lb.

Power
That which is represented by an exponent or index, denoted by a superior small number.

Prime factor
Any factor of a number which is a prime number. There is an infinite number of primes, the first 10 are:2, 3, 5, 7, 11, 13, 17, 19, 23 and 29.

Prime number
A number that has exactly two factors. Hence 1 is not a prime number.

Prism
A solid figure whose cross section is constant in planes drawn perpendicular to its axis .

Probability
Chance, or likelihood, that an event will occur, often expressed as odds, or numerically as a fraction or decimal.

Problem solving
Way of solving problems efficiently, involving a special set of skills.

Product
The result obtained from multiplying two numbers or variables.

Program
Set of instructions that control the operation of a computer.

Progression
Sequence of numbers each formed by a specific relationship to its predecessor.

Projectile
An object ejected into the air.

Pronic number
A number of the form n(n+1) .

Proof
A set of arguments used to deduce a mathematical theorem from a set of axioms.

Proper fraction
A fraction whose value is less than 1.

Proportion
The relation of a part to the whole, usually expressed as a fraction or percentage.

Protractor
Instrument used to measure a flat angle.

Prove
To demonstrate the truth of a proposition by reasoning.

Pyramid
In geometry, a solid figure with triangular side-faces meeting at a common point and with a polygon as its base.

Pythagoras' Theorem
In geometry, a theorem stating that in a right-angled triangle, the area of the square on the hypotenuse is equal to the sum of the areas of the squares drawn on the other two sides. If the hypotenuse is a units long and the lengths of the other sides are b and c, then a = b + c .

Pythagorean triple
An ordered set of three positive integers (a,b,c) such that a2 + b2 = c2.

Words beginning with the letter Q

QED
Abbreviation for quod erat demonstrandum, used to denote the end of a proof.

One quarter of the circumference of a circle. Also, on a graph, the first quadrant lies in the region where both x and y are positive. The remaining three quadrants are numbered in an anticlockwise direction.

Square free.

An equation containing as its highest power the square of a variable, such as x . The general formula of such an equation is ax2 + bx + c = 0 in which a,b and c are real numbers, and only the coefficient a cannot equal 0. In coordinate geometry, a quadratic function represents a parabola, and the quadratic equation may be solved to find the points where the parabola intercepts the x-axis.

The quadrature of a geometric figure is the determination of its area.

An algebraic expression consisting of 4 terms.

Quartic polynomial
A polynomial of degree 4.

A plane figure with four straight sides. Squares, rectangles, parallelograms and trapeziums are all examples of quadrilaterals.

Quantity
A property of an entity that can be represented by numbers.

Quarter
Any of the four equal parts of a whole.

Quartile
In statistics, any one of the three values of a variable that divide its distribution into four parts of equal frequency. They are the lower quartile (or 25th percentile), the median (or 50th Percentile) and the upper quartile (or 75th percentile). The difference of value between the upper and lower quartiles is called the interquartile range.

Quintic polynomial
A polynomial of degree 5.

Quotient
The result of dividing one number or variable into another.

A number that is equal to 1015. This is equal to 10*10*10*10*10*10*10*10*10*10*10*10*10*10*10, or 1 000 000 000 000 000.

Quart
Standard Imperial unit for measuring capacity

A polygon with four angles and four sides. Can be converx or concave.

Qualitative Data
Data that is hard to measure, and is therefore just placed in categories, e.g. favourite food, clothes, etc.

Quantative Data
Data that can be counted (discrete data) or measured (continuous data).

Words beginning with the letter R

An alternative unit to the degree for measuring angles. Radians are commonly used to specify angles in polar coordinates. Symbol rad. One radian = 180/π degrees. One radian is approximately 57.3o.

The locus of points of equal power with respect to two circle.

The radical centre of three circles is the common point of intersection of the radical axes of each pair of circles.

The generalization of decimal point to bases of numeration other than base 10.

A straight line from the centre of a circle to its circumference, or from the centre to the surface of a sphere.

Random event
An event which is allowed to occur without any attempt being made to bias the outcome or consequence of the event.

Random numbers
A sequence of figures in which all figures within a certain range have an equal chance of occurring at equal frequencies over a given period.

Range
In statistics, a measure of dispersion in a frequency distribution, equal to the difference between the largest and smallest values of the variable.

Range
Of a function, the numbers on to which the base set of numbers is mapped.

Rate of change
Change per unit of time.

Ratio
Measure of the relative size of two quantities or of two measurements (in similar units), expressed as a proportion.

Rational number
Any number that can be expressed as an exact fraction.

Real number
Any of the rational numbers, integers or irrational numbers.

Reciprocal
The result of dividing a given quantity into 1. The reciprocal of the number x is the number .

Rectangle
Quadrilateral with opposite sides equal and parallel and with each interior angle a right angle.

Rectangular axis
Another name for Cartesian axis.

Rectangular hyperbola
The graph of the function y = .

Rectangular prism
Another name for a cuboid.

Recurring decimal
Any decimal fraction that never ends but goes on repeating a number or group of numbers after the decimal point.

Reduce
To make smaller.

Reduce to lowest terms
To cancel a fraction to its lowest common factor.

Re-entrant polygon
A polygon that is not completely convex.

Reflection
A transformation that maps a shape across a line so that the line forms an axis of symmetry.

Reflex angle
An angle greater than 180o but less than 360o.

Region
A space enclosed by arcs in a network. In a closed network the number of nodes, arcs and regions are connected by
nodes + regions = arcs + 2.

Regular
Of geometric figures, having all angles and sides equal. Also of solids, having bases comprised of regular polygons.

Relation
A connection between two sets of numbers.

Remainder
The part left over when one number cannot be exactly divided by another.

Repdigit
An integer all of whose digits are the same.

Repunit
An integer consisting only of 1's.

Representative fraction
The scale used in an enlargement, expressed as a fraction.

Rhombus
An equilateral parallelogram also known as a diamond.

Right angle
An angle of 90o.

Right-angled triangle
Triangle in which one of the angles is a right angle.

Roman numerals
Ancient European number system using symbols different from Arabic numerals. The 7 key symbols are I (1), V (5), X (10), L (50), C (100), D (500) and M(1000).

Root
Of an equation, a value that makes the equation true.

Root
The inverse of an exponent.

Root-mean-square
Value obtained by taking the square root of the mean of a set of values.

Root of unity
A solution of the equation x=1, where n is a positive integer.

Rotation
A transformation in which a figure is turned about a given point, known as the centre of rotation.

Rounding
A process by which a number is approximated to the nearest above or below with one less decimal place.

Route
A pathway on a network.

Row
In a matrix, a horizontal line of numbers. Here there are three rows, the first row comprising of the digits 6, 7 and 2.

Words beginning with the letter S

Sample
In statistics, a small set taken from a larger one in order to construct or test a theory about the whole.

Satisfy
The process in which values of variables are said to satisfy equations because they make the equation true.

Scalar quantity
A quantity that has magnitude but no direction.

Scale
The numerical relationship between the actual size of an object and the size of an image that represents it on a map, plan or diagram. Scale is expressed as a ratio.

Scale factor
Of an enlargement, the factor by which the original object is multiplied in order to achieve an enlarged image.

Scalene triangle
A triangle with unequal sides.

Scatter diagram
A diagram used to establish whether or not a connection or correlation exists between two variables. Also known as a scattergram.

Secant
In trigonometry, the function of a given angle in a right-angled triangle, obtained by dividing the length of the hypotenuse by the length of the side adjacent to the angle.

Second
One-sixtieth of a minute.

Sector
Part of a circle enclosed by two radii and the arc that joins them.

Segment
Of a line, the part between two points.

Segment
Part of a circle cut off by a straight line, running from one point on the circumference to another.

Semi
Prefix meaning half.

Sense
The orientation of a vector.

Sequence
Set of elements arranged in order according to some rule.

Series
The sum of the terms of a sequence.

Set
Any collection of defined things (elements), provided the elements are distinct and that there is a rule to decide whether an element is a member of a set. Sets and their interrelationships are often illustrated by a Venn diagram. Below we can see the Venn diagram for two intersecting (overlapping) sets A and B.

Shape
The form of an object, defined by its outline.

Sign
Symbol that indicates whether a number is positive or negative, the operation that is to be carried out on a number or set of numbers, or the relationship that exists between two numbers or sets of numbers.

Significant figures
The figures in a number that, by virtue of their place value, express the magnitude of that number to a specified degree of accuracy. The final significant figure is rounded up if the following digit is greater than 5.

Similar
Of plane or solid figures, having the same shape but a different size or orientation. Similar figures may be produced by enlargement. Two similar figures will have the same corresponding angles, and the ratio of the lengths of their corresponding sides or edges will be constant.

Simplify
Of a fraction, to reduce to lowest terms. Also in algebra, to condense an algebraic expression by grouping similar terms and reducing constants to their lowest terms.

Simultaneous equations
One of two or more algebraic equations that contain two or more unknown quantities that may have a unique solution.

Sine
In trigonometry, a function of an angle in a right-angled triangle found by dividing the length of the side opposite the angle by the length of the hypotenuse. Usually shortened to sin.

Sine rule
Rule in trigonometry that relates the sides and angles of a triangle, stating that the ratio of the length of each side and the sine of the angle is constant. If the sides of a triangle are a, b, and c, and the angles opposite are A, B, and C, respectively, then the sine rule is shown below:

Skeleton division
A long division in which most or all of the digits have been replaced by asterisks to form a cryptarithm.

Skew distribution
In statistics, a distribution in which frequencies are not balanced about the mean.

Skew lines
Straight lines that are not parallel and yet do not meet since they lie in a different plane.

Slide rule
Mathematical instrument with pairs of logarithmic sliding scales, used for rapid calculations.

Slope

Solid of revolution
A solid formed by rotation a plane figure about an axis in three-space.

Solidus
The slanted line in a fraction such as a/b dividing the numerator from the denominator.

Solution
In algebra, the value of a variable that satisfies a given equation.

Solution set
The set of values that satisfies and inequality relationship. For example, 6 < b < 10, where b is an integer has the solution set [ 7, 8, 9].

Solve
To find the answer to a problem or the roots of an equation.

Speed
The rate at which an object moves. Speed may be expressed as v = s/t , where v is the constant speed and s is the distance it has travelled, and t is the time taken to do so.

Speed-time graph
Graph used to describe the motion of a body by illustrating how its speed or velocity changes. The gradient of the graph gives the objectÆs acceleration, and the area under the graph gives the total distance travelled by the body.

Sphere
A perfectly round solid with all points on its surface the same distance from the centre.
For a sphere of radius r, the volume, V
V = 4/3π3
For a sphere of radius r, the Surfacr Area, A
A = 4π2.

Spiral
A plan curve formed by a point winding round a fixed point from which it distances itself at regular intervals.

In computing, a program that mimics a sheet of ruled paper, divided into columns and rows. The user enters values in the sheet, then instructs the program to perform some operation on them. Spreadsheets are widely used in business for forecasting and financial control.

Square
A four-sided plane figure with all sides equal and each angle a right angle. Also, any quantity multiplied by itself is termed a square.

Square number
A number of the form n2.

Square root
A number that when multiplied by itself equals a given number. For example, the square root of 36 (written √36) is 6 because 6 x 6 = 36. Symbol √

Standard
Measure against which others are compared.

Standard deviation
In statistics, a measure of the spread of data. The deviation (difference) of each data item from the mean is found, and their values squared. The mean value of these squares is then calculated. The standard deviation is the square root of this mean.

Standard form
A method of writing very large or very small numbers, often used by scientists.

Statistics
Branch of mathematics concerned with the collection and interpretation of data. Statistics has many applications in government, business, industry and commerce.

Straight line
A line that does not bend or curve.

Subject
The term in a formula that is found by substituting values for the other variables. For example, V is the subject of the formula V = 4/3π3. Often formulae have to be arranged so that a different variable becomes the subject.

Subset
Set drawn from a larger set. In the Venn Diagram below we can see that B is a subset of A. i.e. all the elements of B are in A.

Substitute
To put values in the place of variables in an algebraic expression or formula. An algebraic expansion or simplification can be checked by substituting simple variables for each value.

Subtraction
Taking one number or quantity away from another.

Supplementary
Two angels are supplementary of they add up to 180o.

Surd
An expression containing the root of an irrational number that can never be exactly expressed.

Surface area
The area of the outer surface of a three-dimensional shape or solid.

Survey
In statistics, a method of collecting data in which people are asked to answer a number of questions.

Symbol
A letter, figure, or sign used to represent a word or sentence.

Symmedian
Reflection of a median of a triangle about the corresponding angle bisector.

Symmetry
Exact likeness in shape about a given line (axis), point or plane. A figure has symmetry if one half can be rotated or reflected onto the other. A square has 4 lines of symmetry.

A cuboid has 3 planes of symmetry

Words beginning with the letter T

Table
Collection of information arranged so that information is easy to find.

Tabulate
To organize numbers or data in a table.

Tangent
In geometry, a straight line that touches a curve and has the same gradient as the curve at the point of contact.

Tangent
In trigonometry, a function of an acute angle in a right-angled triangle, defined as the ratio of the length of the side opposite the angle to the length of the side adjacent to it. Sometimes shortened to Tan.

Terminating decimal
Decimal fraction with a finite number of digits.

Tessellation
Tiling pattern that covers space without leaving any gaps.

Tetrahedron
In geometry, a solid figure with four triangular faces. A regular tetrahedron has equilateral triangles as its faces.

Tetromino
A four-square polyomino.

Theorem
Mathematical propostion that can be deduced by logic from a set of axioms.

Thousand
Ten hundreds, 1 000 or 103

Ton
Imperial unit of mass.

Tonne
The metric ton, equal to 0.9842 of an imperial ton.

Toeplitz matrix
A matrix in which all the elements are the same along any diagonal that slopes from northwest to southeast.

Topology
Branch of geometry that deals with those properties of a figure that remain unchanged even when the figure is transformed. The figures below are topologically equivalent.

Torus
A shape with a hole in the middle like a doughnut.

Transcendental number
A number that is not algebraic.

Transformation
A function or mapping, particularly one that causes a change of shape or position in a geometric figure. The main geometrical transformations are reflection, enlargement, rotation and translation.

Translation
A transformation in which a figure is moved or slid to another position without turning.

Transversal
A line cutting two or more lines, usually parallel, in the same plane.

Trapezium
A quadrilateral with two of its sides parallel. An isosceles trapezium has its sloping sides equal, and is symmetrical about a line drawn through the midpoints of its parallel lines.

Travel graph
A type of distance-time graph which shows the stages of a journey.

Tree diagram
A diagram which is used to establish probabilities.

Trial
In a probability experiment, each experiment or observation is called a trial.

Trial and improvement method
A method of solving problems that involves making a first attempt and using the information that this gives to make a better second attempt. This helps the problem solver to get nearer to a solution.

Triangle
A three sided plane figure, the sum of whose interior angles is 180o. Triangles can be classified by the relative lengths of their sides. A scalene triangle has no sides of equal length; an isosceles triangle has at least two equal sides; an equilateral triangle has three equal sides and angles. A right-angled triangle has one angle of 90o.
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Triangular number
Any number that will form an equilateral triangle when arranged in dots. A number of the form n(n+1)/2.

Trinomial
An algebraic expression consisting of 3 terms.

Tromino
A three-square polyomino.

Trigonometry
Branch of mathematics that solves problems relating to plane and spherical triangles. Its principles are based on the fixed proportions of sides for a particular angle in a right-angled triangle, the simplest of which are known as the sine, cosine and tangent. Using trigonometry, it is possible to calculate the lengths of the sides and the sizes of the angles of a right-angled triangle as long as one angle and the length of one side are known, or the lengths of two sides.

Twin primes
Two prime numbers that differ by 2. For example, 11 and 13 are twin primes.

Words beginning with the letter U

Unilateral surface
A surface with only one side, such as a Moebius strip.

Unimodal
A finite sequence is unimodal if it first increases and then decreases.

Unimodular
A square matrix is unimodular if its determinant is 1.

Union
A set which is formed by joining up two or more other sets.

Unit
Standard quantity in relation to which other quantities are measured.

Unit matrix
The matrix which is the identity for multiplication in a family of matrices. The matrix is full of zeroÆs apart from the leading diagonal which is made up of ones. Below is the 3 x 3 unit matrix.

Unit circle
A unit circle is a circle with radius 1.

Unit cube
A cube with edge length 1.

Unit fraction
A fraction whose numerator is 1.

Unit square
A unit square is a square of side length 1.

Universal set
The set from which subsets are taken, the set of all the objects under consideration in a problem.

Upper bound
A value that is greater than or equal to all the values of a given set. The upper bound of a measurement is taken as the top extreme of the possible values.

Unequal
Two things are unequal when they are not the same as each other in terms of quantity or amount. Opposite to equal.

Words beginning with the letter V

Value
A number or other fixed quantity applied to a variable.

Variable
A quantity that can take various values.

Variation
A practical relationship between two variables.

Vector quantity
Any physical quantity that has both magnitude and direction, such as the velocity of an object. A vector is either represented geometrically by an arrow whose length corresponds to its magnitude and points in an appropriate direction, or by a pair of numbers written vertically and placed within brackets.

Velocity
Speed of an object in a given direction.

Venn diagram
A diagram representing a set or sets and the logical relationship between them. The sets are drawn as circles. An area of overlap between two circles (sets) contains elements that are common to both sets, and thus represents a third set.

Vertex
In geometry, a point shared by three or more sides of a solid figure (the corners); the point farthest from a figureÆs base; or the point of intersection of two sides of a plane figure or the two rays of an angle. The plural is vertices.

Vertical
At right angles to the horizontal plane.

Vigesimal
Related to intervals of 20.

Vinculum
The horizontal bar in a fraction separating the numerator from the denominator.

Volume
In geometry, the space occupied by a three-dimensional solid object. A prism or a cylinder has a volume equal to the area of the base multiplied by the height. For a pyramid or cone, the volume is equal to one-third of the area of the base multiplied by the perpendicular height. The volume of a sphere is equal to, V = 4/3π3where r is the radius.

Vulgar fraction
A fraction comprising natural or whole numbers and written as a ratio, rather than in decimal form, e.g. a/b. Also called common fractions or simple fractions.

Words beginning with the letter W

Weigh
To measure the mass of an object.

Weight
The force exerted on an object by gravity. Weight depends on mass and on the strength of the EarthÆs gravitational pull.

Width
The measurement of an object from one side to the other.

Witch of Agnesi
A curve whose equation is x2y=4a2 (2a-y).

Whole
All, complete, total amount. For example, if a circle was cut up into four pieces, you would not have the whole of the circle unless you had all of the four parts.

Whole Number
A number that is complete, i.e. has no fractional part.

Words beginning with the letter X

X-axis
The horizontal axis in the plane.

X-intercept
The point at which a line crosses the x-axis.

X-pentomino
A pentomino in the shape of the letter X.

X-Coordinate
The position of a point on a graph according to the X-Axis.

X-axis
The horizontal axis in the plane.

X-intercept
The point at which a line crosses the x-axis.

X-pentomino
A pentomino in the shape of the letter X.

X-Coordinate
The position of a point on a graph according to the X-Axis.

Words beginning with the letter Y

Y-axis
The vertical axis in the plane.

Y-intercept
The point at which a line crosses the y-axis.

Yard
Imperial unit of length.

Year
A measure of time equal to the period of one revolution of the earth about the sun. Approximately equal to 365.25 days, hence every fourth year an extra day is added (leap year).

Y-Coordinate
The position of a point on a graph according to the Y-Axis.

Words beginning with the letter Z

Z-intercept
The point at which a line crosses the z-axis.

Zero
Written 0, the number that results when any number is subtracted from itself, or added to its negative.