axis

noun ax·is \ˈak-səs\

: the imaginary straight line that something (such as the Earth) turns around

: a straight line that divides a shape evenly into two parts

plural ax·es \-ˌsēz\

Full Definition of AXIS

a : a straight line about which a body or a geometric figure rotates or may be supposed to rotate

b : a straight line with respect to which a body or figure is symmetrical —called also axis of symmetry

c : a straight line that bisects at right angles a system of parallel chords of a curve and divides the curve into two symmetrical parts

d : one of the reference lines of a coordinate system

a : the second vertebra of the neck on which the head and first vertebra turn as on a pivot

b : any of various central, fundamental, or axial parts

: a plant stem

: one of several imaginary lines assumed in describing the positions of the planes by which a crystal is bounded and the positions of atoms in the structure of the crystal

: a main line of direction, motion, growth, or extension

a : an implied line in painting or sculpture through a composition to which elements in the composition are referred

b : a line actually drawn and used as the basis of measurements in an architectural or other working drawing

: any of three fixed lines of reference in an aircraft that run in the longitudinal, lateral, and vertical directions, are mutually perpendicular, and usually pass through the aircraft's center of gravity

: partnership, alliance

: a point or continuum on which something centers <an axis of social power>

See axis defined for English-language learners

See axis defined for kids

Origin of AXIS

Latin, axis, axle; akin to Old English eax axis, axle, Greek axōn, Lithuanian ašis, Sanskrit akṣaḥ

First Known Use: 14th century

Related to AXIS

Synonyms: center, base, capital, central, core, cynosure, epicenter, eye, focus, ground zero, heart, hub, locus, mecca, navel, nerve center, nexus, nucleus, omphalos, seat

Other Astronomy Terms

gibbous, nadir, nebulous, penumbra, retrograde, sidereal, syzygy, wane, wax, zenith

Rhymes with AXIS

Naxos, praxis

Axis

adjective

Definition of AXIS

: of or relating to the three powers Germany, Italy, and Japan engaged against the Allied nations in World War II

First Known Use of AXIS

1938

Other History Terms

agonistic, carpetbagger, enceinte, fief, historiography, paladin

AXIS Defined for Kids

axis

noun ax·is \ˈak-səs\

plural ax·es \ˈak-ˌsēz\

Definition of AXIS for Kids

: a straight line about which a body or a geometric figure rotates or may be thought of as rotating <the earth's axis>

: a line of reference used to assign numbers to locations in a geometric plane

Medical Dictionary

axis

noun ax·is \ˈak-səs\

plural ax·es \-ˌsēz\

Medical Definition of AXIS

a : a straight line about which a body or a geometric figure rotates or may be thought of as rotating b : a straight line with respect to which a body, organ, or figure is symmetrical

a : the second vertebra of the neck of the higher vertebrates that is prolonged anteriorly within the foramen of the first vertebra and united with the dens which serves as a pivot for the atlas and head to turn upon—called also epistropheus b : any of various central, fundamental, or axial parts <the cerebrospinal axis> <the skeletal axis> c : axilla