ax·​is | \ ˈak-səs How to pronounce axis (audio) \
plural axes\ ˈak-​ˌsēz How to pronounce axis (audio) \

Definition of axis

 (Entry 1 of 2)

1a : 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 coordinate entry 3 sense 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
6a : 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



Definition of Axis (Entry 2 of 2)

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

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Examples of axis in a Sentence

Noun the Earth's axis of rotation the spin of the Earth on its axis
Recent Examples on the Web: Noun The natural processes are visible in real time, with 250,000-year-old Tybee Island slowly rotating on an axis. Patrik Jonsson, The Christian Science Monitor, 15 Sep. 2021 Seemingly undeterred by mounting Delta variant numbers, the rollicking crowd rocked the sports world back onto its axis, if only for a moment, a replay of the scenes from college football last weekend. Sam Farmer, Los Angeles Times, 9 Sep. 2021 The earth’s current relationship with its axis is ultimately a matter for debate but on the eve of Alabama’s last Labor Day trip to Atlanta, the impact of the first one still echoes through college football. Michael Casagrande |, al, 30 Aug. 2021 Solstice is connected only to the fact that Earth spins on an axis that is tilted by 23.5°. Jamie Carter, Forbes, 17 June 2021 The monthly habit, or vertical axis, is the strategy part of this method. Simon Severino, Forbes, 2 Sep. 2021 Away from the boardroom, his perennially high social axis also took its toll, something which Murphy’s high-voltage rendition doesn’t pull any punches on. Julia Hobbs, Vogue, 9 May 2021 Brandon arrives on the beach and Serena’s head positively swivels off its axis. Ali Barthwell, Vulture, 17 Aug. 2021 Human observers know that at night the stars trace circles in the sky as Earth spins on its axis. New York Times, 29 July 2021

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.

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First Known Use of axis


14th century, in the meaning defined at sense 1a


1938, in the meaning defined above

History and Etymology for axis


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

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Time Traveler for axis

Time Traveler

The first known use of axis was in the 14th century

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Dictionary Entries Near axis



axis cylinder process

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Statistics for axis

Last Updated

19 Sep 2021

Cite this Entry

“Axis.” Dictionary, Merriam-Webster, Accessed 21 Sep. 2021.

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More Definitions for axis



English Language Learners Definition of axis

: the imaginary straight line that something (such as the Earth) turns around
: a straight line that divides a shape evenly into two parts


ax·​is | \ ˈak-səs How to pronounce axis (audio) \
plural axes\ ˈak-​ˌsēz \

Kids Definition of axis

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


ax·​is | \ ˈak-səs How to pronounce axis (audio) \
plural axes\ -​ˌsēz How to pronounce axis (audio) \

Medical Definition of axis

1a : 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
2a : 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

More from Merriam-Webster on axis

Nglish: Translation of axis for Spanish Speakers

Britannica English: Translation of axis for Arabic Speakers Encyclopedia article about axis


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