axis

noun9

1. •
   An imaginary line around which an object spins (an axis of rotation) or is symmetrically arranged (an axis of symmetry).

   • The Earth rotates once a day on its axis
2. •
   An imaginary, visualized plane separating two morphologically similar parts of an organism
3. •
   (figurative) The centre of attention within a process (e.g. the axis of investigation)
4. •
   A fixed one-dimensional figure, such as a line or arc, with an origin and orientation and such that its points are in one-to-one correspondence with a set of numbers; an axis forms part of the basis of a space or is used to position and locate data in a graph (a coordinate axis)
5. •
   An alliance or coalition.

   • This Berlin-Madrid vertical line is not an obstacle but rather an axis around which can revolve all those European states with a will to collaboration and peace. — 1936
6. •
   The second cervical vertebra of the spine
7. •
   The main stem or central part about which organs or plant parts such as branches are arranged
8. •
   A form of classification and descriptions of mental disorders or disabilities used in manuals such as the DSM (Diagnostic and Statistical Manual of Mental Disorders)
9. •
   A deer native to Asia, of species Axis axis.