the line about which a rotating body, such as the earth, turns.

Mathematics .

a central line that bisects a two-dimensional body or figure.

a line about which a three-dimensional body or figure is symmetrical.

Anatomy .

a central or principal structure, about which something turns or is arranged

the skeletal axis.

the second cervical vertebra.

Botany . the longitudinal support on which organs or parts are arranged; the stem and root; the central line of any body.

Analytic Geometry . any line used as a fixed reference in conjunction with one or more other references for determining the position of a point or of a series of points forming a curve or a surface. Compare x-axis , y-axis .

Crystallography . crystallographic axis.

Aeronautics . any one of three lines defining the attitude of an airplane, one being generally determined by the direction of forward motion and the other two at right angles to it and to each other.

Fine Arts . an imaginary line, in a given formal structure, about which a form, area, or plane is organized.

an alliance of two or more nations to coordinate their foreign and military policies, and to draw in with them a group of dependent or supporting powers.

the Axis, (in World War II) Germany, Italy, and Japan, often with Bulgaria, Hungary, and Romania.

a principal line of development, movement, direction, etc.

noun

arbor , axle , hinge , pivot , pole , shaft , spindle , stalk , stem , support , turning point , alliance , coalition , deer , fulcrum