ax ‧ is /ˈæksəs, ˈæksɪs/ BrE AmE noun ( plural axes /-siːz/) [countable]
[ Date: 1300-1400 ; Language: Latin ; Origin: 'axis, axle' ]
1 . the imaginary line around which a large round object, such as the Earth, turns:
The Earth rotates on an axis between the north and south poles.
2 . a line drawn across the middle of a regular shape that divides it into two equal parts
3 . either of the two lines of a ↑ graph , by which the positions of points are measured
the vertical/horizontal axis