Edexcel GCSE Mathematics Key Terms

A value that, when raised to the power n, equals the original number.

A timekeeping system that resets at midday, using a.m. for morning and p.m. for afternoon/evening.

A timekeeping system that runs continuously from 00:00 to 23:59 without resetting at midday.

A condition that proves two triangles are mathematically similar, but not necessarily congruent, as all corresponding angles are equal.

A condition for triangle similarity where two corresponding angles are equal.

The distance a number is from zero on a number line, representing its size without regard to its sign.

The rate of change of velocity, represented by the gradient of a velocity-time graph.

The total sum of the original principal and all the compound interest earned to date.

A method for factorising non-unitary quadratics by splitting the middle term (bx) into two separate terms to allow for grouping.

The real-world distance between two points, usually expressed in metres or kilometres.

An angle measuring strictly less than 90°.

The mathematical rule stating that for mutually exclusive events, the probability of either event occurring is the sum of their individual probabilities.

Angles that share a common vertex and a common side, lying flat on a continuous straight line, summing to 180°.

The side next to the reference angle being considered, connecting it to the right angle, which is not the hypotenuse.

A mathematical statement containing numbers, variables, and operators, but strictly no equals sign.

A fraction where the numerator and/or denominator contain algebraic expressions.

A logical argument using general algebraic terms to show a mathematical statement is true for all possible values.

The process of replacing a variable in an expression with another mathematical expression or value.

Angles on opposite sides of a transversal crossing parallel lines, which are always equal.

The segment on the opposite side of a chord from the angle between that chord and a tangent.

A situation in trigonometry using the Sine Rule where the calculated acute angle should actually be its obtuse supplement (180° - angle) based on the context of the diagram.

The maximum displacement from the equilibrium (the $x$-axis). For $y = \sin x$ and $y = \cos x$, this is .

A straight line that divides an angle into two exactly equal parts.

A set of angles that share a common vertex and whose exterior boundaries form a complete circle, summing to 360°.

A set of adjacent angles that form a straight angle; they must sum exactly to 180 degrees.

The ring-shaped region between two concentric circles.

The top vertex of a 3D shape such as a pyramid or cone.

The angle located between the two equal sides of an isosceles triangle.

A valid answer within an examiner-approved range, typically derived from reading a hand-drawn graph.

A value that is nearly but not exactly correct, often found through repeated mathematical iteration.