axis

noun ax·is \ ˈak-səs \
Updated on: 7 Dec 2017

Definition of axis

plural axes play \-ˌsēz\
1 a : a straight line about which a body or a geometric figure rotates or may be supposed to rotate
  • the Earth's axis
b : a straight line with respect to which a body or figure is symmetrical
  • the axis of a cone
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 (see 3coordinate 1a)
2 anatomy
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
3 botany : a plant stem
4 crystallography : 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
5 : a main line of direction, motion, growth, or extension
  • the axis of a city
6 a : an implied line in painting or sculpture through a composition to which elements in the composition are referred
  • fruit and flowers arranged about a diagonal axis
b : a line actually drawn and used as the basis of measurements in an architectural or other working drawing
7 aviation : 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
8 : partnership, alliance
  • an axis of countries
9 : a point or continuum on which something centers
  • an axis of social power

Examples of axis in a Sentence

  1. the Earth's axis of rotation

  2. the spin of the Earth on its axis

Recent Examples of axis from the Web

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'axis.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Origin and Etymology of axis

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

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


AXIS Defined for English Language Learners

axis

noun

Definition of axis for English Language Learners

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

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


AXIS Defined for Kids

axis

noun ax·is \ ˈak-səs \

Definition of axis for Students

plural axes \ˈak-ˌsēz\
1 : a straight line about which a body or a geometric figure rotates or may be thought of as rotating
  • the earth's axis
2 : a line of reference used to assign numbers to locations in a geometric plane

Medical Dictionary

axis

noun ax·is \ ˈak-səs \

medical Definition of axis

plural axes play \-ˌsēz\
1 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
2 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


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