Maths glossary
Clear, plain-English definitions of the maths and teaching terms that come up most, each with examples and free worksheets to practise.
An acute angle is smaller than a right angle, less than 90 degrees.
Addition is combining two or more amounts to find how many there are altogether.
An adjective is a word that describes a noun.
An adverb is a word that tells you more about a verb, often how, when or where.
Alliteration is when nearby words begin with the same sound.
An angle is the amount of turn between two lines that meet at a point.
An antonym is a word that means the opposite of another word.
Area is the amount of flat space a 2D shape covers, measured in square units.
An array arranges objects in equal rows and columns to show multiplication.
The associative property means the way numbers are grouped does not change the answer for addition and multiplication.
A bar graph shows and compares amounts using bars of different lengths.
Capacity is how much a container can hold, usually measured in litres and millilitres.
The circumference is the distance all the way around a circle.
The commutative property means the order of the numbers does not change the answer for addition and multiplication.
A composite number has more than two factors.
Two shapes are congruent if they are exactly the same size and shape.
A conjunction is a joining word that links words or sentences, like and, but or because.
A consonant blend is two or three consonants read together, with each sound still heard.
Coordinates are a pair of numbers that give the exact position of a point on a grid.
A decimal uses a point to show parts of a whole smaller than one.
The difference is the answer you get when you subtract one number from another.
A digit is a single number symbol from 0 to 9.
A digraph is two letters that together make one sound.
The distributive property lets you multiply a sum by multiplying each part and adding the results.
Division shares an amount into equal groups, or finds how many equal groups fit.
An equation is a number sentence that says two things are equal, using an equals sign.
Equivalent fractions look different but show the same amount.
An estimate is a close, sensible guess rather than an exact answer.
Even numbers can be split into two equal groups; odd numbers cannot.
Expanded form writes a number as the sum of the value of each digit.
An exponent shows how many times a number is multiplied by itself.
Faces, edges and vertices are the flat surfaces, lines and corners of a 3D shape.
A fact family is a group of related addition and subtraction (or multiplication and division) facts using the same numbers.
A factor is a whole number that divides exactly into another number.
A food chain shows how living things get their energy by eating one another.
A fraction shows equal parts of a whole, written as a numerator over a denominator.
A grapheme is the letter or letters that spell a single sound.
The greatest common factor is the largest number that divides exactly into two or more numbers.
A habitat is the natural home of a plant or animal.
Homophones are words that sound the same but have different meanings or spellings.
An improper fraction has a numerator equal to or bigger than its denominator.
An inequality compares two amounts that are not equal, using signs like < and >.
An inference is a smart guess based on clues and what you already know.
An integer is a whole number, which can be positive, negative or zero.
A life cycle is the series of stages a living thing passes through as it grows.
The lowest common multiple is the smallest number that two or more numbers all divide into.
The main idea is what a text is mostly about.
Mass is how much matter an object contains, measured in grams and kilograms.
The mean is the total of a set of numbers shared equally between them.
The median is the middle value when the numbers are put in order.
A metaphor describes something by saying it is something else.
A mixed number is a whole number and a fraction written together.
The mode is the value that appears most often in a set of data.
A multiple of a number is what you get when you multiply it by a whole number.
Multiplication is repeated addition of equal groups.
A negative number is a number less than zero, written with a minus sign in front.
A net is a flat pattern that folds up to make a 3D shape.
A noun is a word that names a person, place, thing or idea.
A number bond shows how a number splits into two parts that add back to the whole.
A number line is a straight line with numbers marked in order at equal spaces.
The numerator is the top number of a fraction; the denominator is the bottom number.
An obtuse angle is bigger than a right angle but less than a straight line.
The order of operations is the agreed sequence for working out a calculation with more than one step.
Parallel lines are always the same distance apart and never meet.
A percentage is a number out of 100, shown with the % sign.
Perimeter is the total distance around the outside of a shape.
Perpendicular lines cross or meet to make a right angle.
A phoneme is the smallest single sound in a word.
Place value is the idea that a digit's position decides what it is worth.
A polygon is a flat, closed shape made of straight sides.
A prefix is a group of letters added to the start of a word to change its meaning.
A preposition shows where or when something is, like in, on, under or before.
A prime number has exactly two factors: 1 and itself.
A prism is a 3D shape with two identical ends joined by flat sides.
Probability is how likely something is to happen, from impossible to certain.
A product is the answer when you multiply two or more numbers.
A pronoun is a word used in place of a noun, like he, she, it or they.
A proper fraction has a numerator smaller than its denominator, so it is less than one whole.
A quadrilateral is a polygon with four straight sides.
A quotient is the answer to a division.
The radius is the distance from a circle's centre to its edge; the diameter goes all the way across through the centre.
The range is the difference between the largest and smallest values.
A ratio compares two amounts, showing how much of one there is for each amount of the other.
A reflection is a mirror image of a shape flipped over a line.
Regrouping is the carrying and borrowing used in column addition and subtraction.
The remainder is the amount left over after dividing.
A right angle is a quarter turn, measuring exactly 90 degrees.
Roman numerals write numbers using the letters I, V, X, L, C, D and M.
A rotation turns a shape around a fixed point.
Rounding replaces a number with a nearby, simpler one.
Similar shapes are the same shape but different sizes.
A simile describes something by comparing it to something else using 'like' or 'as'.
Simplifying a fraction means rewriting it with the smallest possible numbers.
Skip counting is counting forwards or backwards in equal jumps instead of by ones.
A square number is a number multiplied by itself.
A square root of a number is the value that multiplies by itself to make that number.
The three states of matter are solid, liquid and gas.
Subtraction is taking one amount away from another, or finding the difference between them.
A suffix is a group of letters added to the end of a word to change its meaning or use.
The sum is the answer you get when you add numbers together.
A syllable is a single beat or chunk of sound in a word.
A shape has symmetry if one half is a mirror image of the other.
A synonym is a word that means the same, or nearly the same, as another word.
A tally chart records counts using groups of five tally marks.
A translation slides a shape to a new position without turning or flipping it.
A triangle is a polygon with three straight sides and three corners.
A unit fraction is a fraction with a numerator of 1.
A variable is a letter or symbol that stands for an unknown or changing number.
A verb is a word that shows an action or a state of being.
A vertex is a corner where two or more edges of a shape meet.
Volume is the amount of space a 3D object takes up, measured in cubic units.