axis

Meanings

1. 1nouncountable

   An imaginary straight line through the middle of something, around which it turns or around which its two halves match each other.

   Grammar: Plural is axes, pronounced /ˈæksiːz/: the planet's axis, but two axes.

   Patterns

   • rotate on its axis
   • the axis of something

   The Earth rotates on its axis once every twenty-four hours.

   A circle can be folded along any axis through its centre.

   The spinning top wobbled and then settled on a tilted axis.

2. 2nouncountablemathematics

   One of the fixed reference lines on a graph, usually horizontal or vertical, along which values are marked.

   Grammar: Used with x or y: the x-axis runs across the graph and the y-axis runs up it.

   Patterns

   • on the x-axis
   • along the axis

   Time is plotted on the horizontal axis and temperature on the vertical one.

   Please label both axes of your chart before handing it in.

   The line crosses the y-axis at three.

3. 3nouncountablefigurative

   A central line or idea around which a system, alliance or set of parts is organised.

   Grammar: Often followed by of: the axis of the plot, or the alliance's axis.

   Patterns

   • axis of something
   • the central axis

   The whole story turns on one axis: the friendship between the two sisters.

   Historians refer to Germany, Italy and Japan as the Axis powers in the Second World War.

   The street forms the main axis of the old town.

Word forms

Common combinations

rotate on its axis

Jupiter rotates on its axis faster than any other planet.

the x-axis

Distance in kilometres is measured along the x-axis.

the vertical axis

Sales figures appear on the vertical axis of the graph.

axis of symmetry

The line down the middle of a butterfly's wings is its axis of symmetry.

tilt of the axis

The tilt of the Earth's axis causes the seasons.

Synonyms and how they differ

centre line

Centre line is a plain description of a middle line, but axis is the usual technical term when something turns or is symmetrical around it.

pivot

A pivot is a point or pin on which something turns, while an axis is the whole line of rotation.

hub

Hub is the centre of activity or of a wheel, and unlike axis it is a place or part, not an imaginary line.

Word family

axes noun

the plural of axis

axial adjective

relating to or forming an axis

axle noun

the rod on which a wheel turns, from the same root

biaxial adjective

having two axes

Commonly confused: axis or axes (plural of axe)? axis or axle?

Practice

Make it your own

Write a sentence using “axis”, then check it and compare it with the examples above.

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