Axis: GCSE Mathematics Definition

Roger B

Maths

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2 minutes

What is an axis in GCSE Maths?

In GCSE Maths, axis almost always refers to one of the two lines on a graph that are used to plot points in a coordinate plane. A typical example is shown below, with the point (-3, 4) indicated and labelled ‘A’. 

A graph with labelled point A at (-3, 4) on a Cartesian grid. The x-axis ranges from -6 to 6, and the y-axis ranges from -6 to 6.

The horizontal axis is usually labelled as the ‘x-axis’, and the vertical axis is usually labelled as the ‘y-axis’. The point where the two axes meet is known as the origin. The position of a point can be indicated by its coordinates in the form (x, y), indicating how far along the x-axis and y-axis a point lies (like the point A on the graph above). Sometimes you need to refer to a point in three dimensions, and in this case a z-axis can be added to the x- and y-axes.

In many contexts, the x-axis will be used for the independent (or input) variable, while the y-axis is used for the dependent (or output) variable. It is also important to remember that the axes won’t always be labelled ‘x’ and ‘y’. For example, on a velocity-time graph the horizontal axis will usually be labelled ‘t’ (for time), and the vertical axis will usually be labelled ‘v’ (for velocity).

What is the plural of axis?

When you’re talking about more than one axis, the plural is ‘axes’ (pronounced ‘axe ease’). This is because English borrowed the word ‘axis’ from Latin, where ‘axes’ is the normal plural.

Axis Revision Resources to Ace Your Exams

Axes are a core concept that appear in many different places in our GCSE revision resources. For example, see our revision notes on 2D and 3D coordinates for an introduction. You can also have a go at our related exam questions and flashcards to test your understanding. Don’t forget to check out the past papers for more general exam revision.

Explore GCSE Maths revision resources

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Written by Roger B

Maths6 articles

Roger's teaching experience stretches all the way back to 1992, and in that time he has taught students at all levels between Year 7 and university undergraduate. Having conducted and published postgraduate research into the mathematical theory behind quantum computing, he is more than confident in dealing with mathematics at any level the exam boards might throw at you.

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