1911 Encyclopædia Britannica/Axis  From Wikisource Jump to:
navigation, search  AXIS (Lat. for "axle"), a word having the
same meaning as axle, and also used with many extensions of this
primary meaning. It denotes the imaginary line about which a
body or system of bodies rotates, or a line about which a body
or action is symmetrically disposed. In geometry, and in
geometrical crystallography, the term denotes a line which
serves to aid the orientation of a figure. In anatomy, it is,
among other uses, applied to the second cervical vertebra, and
in botany it means the stem.