Mathematics GCSE
Mathematics GCSE glossary
89 key terms for Mathematics GCSE, A to Z, each linked to the topic pages that use it.
A
- Alternate Angles
- Equal angles formed on opposite sides of a transversal between parallel lines.Pearson Edexcel
- Asymptote
- A straight line that a curve approaches infinitely closely but never touches or crosses.OCR
B
- Base
- The number that is being multiplied by itself when raised to a power.OCR
C
- Circumference
- The specific term for the perimeter of a circle.OCR
- Co-interior Angles
- Angles between parallel lines on the same side of a transversal that sum to $180^\circ$.Pearson Edexcel
- Coefficient
- The number placed in front of a variable, which multiplies it (e.g., in $7x$, 7 is the coefficient).Eduqas
- Common difference
- The constant amount added or subtracted to get from one term to the next in a linear sequence.Pearson Edexcel
- Compound Interest
- Interest calculated on the initial principal and also on the accumulated interest of previous periods.OCR, Pearson Edexcel
- Compound Measure
- A measure made up of two or more other measurements, such as speed (distance and time) or density (mass and volume).Eduqas, Pearson Edexcel
- Conditional Probability
- The probability of an event occurring given that another event has already occurred.Pearson Edexcel
- Congruent
- Shapes that are exactly the same shape and the same size.Eduqas, OCR
- Conjugate
- A binomial formed by negating the second term of a binomial.OCR
- Constant of Proportionality
- The constant value (usually denoted as $k$) that relates two proportional variables.Eduqas
- Continuous Data
- Numerical data that can take any value within a given range, usually measured.Eduqas, Pearson Edexcel
- Corresponding
- Sides or angles that appear in the same relative position in two similar or congruent figures.OCR
- Corresponding Angles
- Equal angles in the same relative position at each intersection where a straight line crosses parallel lines.Pearson Edexcel
- Cross-section
- The two-dimensional shape exposed when a 3D solid is sliced parallel to its base.OCR
- Cyclic Quadrilateral
- A four-sided shape where all four vertices lie on the circumference of a circle.Eduqas
D
- Decimal Place
- The position of a digit to the right of a decimal point.OCR
- Denominator
- The bottom number in a fraction, representing the total number of equal parts the whole is divided into.OCR, Pearson Edexcel
- Dependent Events
- Events where the outcome of one DOES affect the outcome of the other.Pearson Edexcel
- Depreciation
- A decrease in the value of an asset over time.OCR, Pearson Edexcel
- Direct Proportion
- A relationship where two variables increase or decrease at the same constant rate; their ratio remains constant ($y = kx$).Eduqas
- Discrete Data
- Data that can only take specific, exact values (e.g., number of siblings).Eduqas, Pearson Edexcel
E
- Equation
- A mathematical statement showing that two expressions are equal, containing an equals sign (e.g., $2x + 5 = 11$).Eduqas
- Equivalent Fractions
- Fractions that represent the same value or proportion, even though they look different (e.g., 1/2 and 2/4).OCR
- Error Interval
- The range of possible true values that a rounded number could represent, expressed as an inequality.OCR
- Estimation
- Finding a value that is close enough to the right answer, usually by rounding to 1 significant figure.OCR
- Expected Frequency
- The theoretical number of times an event should occur over a given number of trials.Eduqas
- Expression
- A collection of terms separated by plus or minus signs, with NO equals sign (e.g., $2x + 5$).Eduqas
- Extrapolation
- Estimating a value outside the range of the given data points on a scatter graph.Eduqas, Pearson Edexcel
F
- Fibonacci sequence
- A sequence where each term is the sum of the two preceding terms.Pearson Edexcel
- Formula
- A rule written using symbols that describes a relationship between different quantities (e.g., $A = \pi r^2$).Eduqas
- Frequency Density
- The frequency per standard unit of data, calculated as Frequency ÷ Class Width.Eduqas, Pearson Edexcel
- Frustum
- The portion of a cone or pyramid that remains after its upper part has been cut off by a plane parallel to its base.OCR
G
- Gradient
- A measure of the steepness of a line, calculated as the change in y divided by the change in x.OCR, Pearson Edexcel
H
- Hypotenuse
- The longest side of a right-angled triangle, always opposite the right angle.Eduqas
I
- Identity
- An equation that is true for ALL values of the variables involved, often denoted by a triple equals sign $\equiv$ (e.g., $2(x+3) \equiv 2x + 6$).Eduqas
- Included Angle
- The angle formed between two specific sides of a polygon.OCR
- Included Side
- The side shared by two specific angles of a polygon.OCR
- Independent Events
- Events where the outcome of one does not affect the outcome of the other.Eduqas, Pearson Edexcel
- Index (Power/Exponent)
- A number that indicates how many times a base number is multiplied by itself.OCR
- Integer
- A whole number that can be positive, negative, or zero.Eduqas, OCR
- Interquartile Range (IQR)
- The difference between the upper and lower quartiles, representing the middle 50% of the data.Pearson Edexcel
- Intersection
- The set of outcomes that belong to both event A and event B simultaneously.Eduqas
- Intersection (A ∩ B)
- The event that both A and B occur simultaneously.Pearson Edexcel
- Inverse Proportion
- A relationship where one variable increases as the other decreases at a constant rate; their product remains constant ($y = k/x$).Eduqas
- Irrational Number
- A number that cannot be written as a simple fraction; its decimal goes on forever without repeating.Eduqas
L
- Lower Bound
- The smallest possible value a measurement could be before it was rounded up.OCR
M
- Multiplier
- A decimal used to calculate a percentage change in a single step (e.g., 1.20 for a 20% increase).Eduqas, OCR, Pearson Edexcel
- Mutually Exclusive
- Events that cannot happen at the same time.Eduqas, Pearson Edexcel
N
- Numerator
- The top number in a fraction, representing how many parts of the whole are being considered.OCR, Pearson Edexcel
O
- Outlier
- An extreme value that lies far outside the overall pattern of a data set.Eduqas
P
- Percentage
- A number or ratio expressed as a fraction of 100.Pearson Edexcel
- Percentage Multiplier
- A decimal used to calculate a percentage of an amount or a percentage change in a single multiplication step.OCR
- Perimeter
- The total continuous length of the boundary of a closed two-dimensional figure.OCR
- Position-to-term rule (nth term)
- An algebraic formula that calculates the value of any term based on its position (n) in the sequence.Pearson Edexcel
- Prime Number
- A number with exactly two distinct factors: 1 and itself.Eduqas
- Prism
- A 3D solid with identical parallel ends and a constant cross-section along its entire length.OCR
Q
- Qualitative Data
- Non-numerical data that is descriptive or categorical.Eduqas
R
- Rate of Change
- How one quantity changes in relation to another quantity (e.g., speed is the rate of change of distance with respect to time).Pearson Edexcel
- Ratio
- A mathematical relationship comparing the size or amount of two or more quantities.Eduqas
- Rational Number
- A number that can be expressed as a fraction a/b, where a and b are integers and b is not zero.Eduqas
- Rationalise
- The process of converting an irrational denominator into a rational number.OCR
- Reciprocal
- The reciprocal of a number is 1 divided by that number.OCR
- Recurring Decimal
- A decimal fraction in which a figure or group of figures is repeated indefinitely.OCR
- Regular Polygon
- A 2D shape where all sides are equal in length and all interior angles are equal in size.Eduqas, Pearson Edexcel
- Relative Frequency
- An estimate of probability based on the results of an experiment.Eduqas
- Reverse Percentage
- The process of finding an original amount after a percentage increase or decrease has occurred.OCR, Pearson Edexcel
- Root
- A solution to an equation, represented graphically as the point(s) where the curve crosses the x-axis (where y = 0).OCR
S
- Sample Space
- The set of all possible outcomes of an experiment.Eduqas, Pearson Edexcel
- Scale Factor ($k$)
- The multiplier used to enlarge or reduce a shape.OCR
- Sequence
- An ordered list of numbers that follow a specific mathematical rule.Pearson Edexcel
- Significant Figure
- The digits in a number that carry meaning contributing to its precision, starting from the first non-zero digit.Eduqas, OCR
- Similar
- Shapes that are the same shape but different sizes.Eduqas, OCR
- Simplify
- To divide the numerator and denominator of a fraction by their highest common factor to find an equivalent fraction in its lowest terms.OCR
- Simplify/Lowest Terms
- Dividing the numerator and denominator of a fraction by their highest common factor until they cannot be divided further.OCR
- Standard Form
- A way of writing numbers as A × 10^n, where 1 ≤ A < 10 and n is an integer.Eduqas
- Surd
- An irrational number expressed as a root, which cannot be simplified to a rational number.OCR
- Surface Area
- The total area of all the faces (both flat and curved) of a three-dimensional object.OCR
T
- Tangent
- A straight line that touches a curve at exactly one point without crossing it.Eduqas, OCR
- Term
- A single number, a single variable, or numbers and variables multiplied together (e.g., $4$, $x$, $3xy^2$).Eduqas, Pearson Edexcel
- Term-to-term rule
- A rule that describes how to calculate the next term in a sequence using the previous term.Pearson Edexcel
- Terminating Decimal
- A decimal number that has a finite number of digits after the decimal point.Pearson Edexcel
- Transversal
- A straight line that intersects two or more parallel lines.Pearson Edexcel
- Turning Point
- The local maximum or minimum point on a curve where the gradient is exactly zero.OCR
U
- Upper Bound
- The largest possible value a measurement could be before it was rounded down.OCR
V
- Vertically Opposite
- The pairs of equal angles formed when two straight lines intersect.Pearson Edexcel
Y
- y-intercept
- The point where a graph crosses the y-axis, occurring when x = 0.OCR
Where these terms come from
Each definition is one we publish on a Mathematics GCSE topic page or study guide. Open a term to see how each exam board words it and which topic it belongs to. For the full course, go to Mathematics revision or the glossary for every subject.
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