axis

plural axes · plural rare axiis

1. geometryAn 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

   1 more example

   A doorknob of whatever roundish shape is effectively a continuum of levers, with the axis of the latching mechanism—known as the spindle—being the fulcrum about which the turning takes place.

   2012 March 28, Henry Petroski, “Opening Doors”, in American Scientist, volume 100, number 2, pages 112–3

2. mathematicsA 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)
3. anatomyThe second cervical vertebra of the spine

   Synonyms: epistropheus

4. anatomyAn imaginary, visualized plane separating two morphologically similar parts of an organism
5. human sciencesA form of classification and descriptions of mental disorders or disabilities used in manuals such as the DSM (Diagnostic and Statistical Manual of Mental Disorders)
6. biologyThe main stem or central part about which organs or plant parts such as branches are arranged
7. governmentAn 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, November 1st, Francisco Franco, Bilbao Speech

   Synonyms: pact, compact, league

8. figurativelyThe centre of attention within a process (e.g. the axis of investigation)

plural axises

1. A deer native to Asia, of species Axis axis.

   Synonyms: chital, cheetal, chital deer, spotted deer, axis deer

1. The alliance (in effect before and during World War II) of Germany, Italy, Japan, and several minor allied countries, which opposed the Allies.First known use 20th c.

   Synonyms: the Axis Powers