(geometry) Any of one or more lines about which a geometric figure is symmetric

(mathematics) The horizontal line in the complex plane, every point on which corresponds to a real number

(mathematics) The vertical line in the complex plane, every point on which corresponds to a complex number having zero real component

(mathematics) The line containing the locus of points from which the segments respectively tangent to two given circles have equal length.

The axis about which any body rotates. / The line joining the North Pole and South Pole about which the Earth rotates daily.

plural of Axis power

The optical axis. / (crystallography, mineralogy) The direction in which a ray of light passing through a crystal does not suffer double refraction.

(geometry) Either of two axes in a conic section, such that each is parallel to the tangent at the extremity of the other.

(chiefly in the plural) A country in the alliance (in effect before and during World War II) of Nazi Germany, fascist Italy, imperial Japan, and a few other countries, which opposed the Allies.

A South Asian deer, the chital, Axis axis