: 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
Noun the Earth's axis of rotation the spin of the Earth on its axis
Recent Examples on the Web
Noun
Earth spins on its axis at about 1,000 miles per hour, or 1,525 feet per second at the equator. Manasee Wagh, Popular Mechanics, 16 Aug. 2022 Earth's rotation on its axis determines our daily cycle of sunrise and sunset. Sarah Raza, USA TODAY, 5 Aug. 2022 To achieve the tilt, which can slant the car at as much as 33 degree angle from the vertical axis, Nimbus relies on an electromechanical system that combines sensors, actuators, and software. Alexei Oreskovic, Fortune, 9 Aug. 2022 The program targets the microbiome-gut-brain axis for mental health, which is important because of its potential benefit to issues like anxiety, depression and stress response. Jess Cording, Forbes, 4 Aug. 2022 Balance cannot be thrown off of its axis, explained Alabama’s coach. Joseph Goodman | Jgoodman@al.com, al, 19 July 2022 Bucherer and Jacob & Co teamed up to create a one-of-a-kind triple-axis tourbillon, the Jacob & Co. Astronomia Tourbillon Bucherer Blue. Carol Besler, Forbes, 21 June 2022 Enough of them are also disgusting, which is the axis on which Keene will turn from a person who cares mostly about himself into a man with a conscience. Robert Lloyd, Los Angeles Times, 7 July 2022 The gas from the reactions escapes out the small hole where the fuse once went into the firework, which propels the firework along its center axis. Popular Mechanics Editors, Popular Mechanics, 30 June 2022 See More
Word History
Etymology
Noun
Middle English, "imaginary line passing through the center of a body, celestial axis," borrowed from Latin, "axletree, axle, chariot, celestial axis," going back to Indo-European *h2eḱs- "axle," whence also, with varying thematic derivation, Germanic *ahsō (whence Old English eax "axle," Old Saxon & Old High German ahsa), Old Russian/Eastern Church Slavic osĭ "axle," Bosnian-Croatian-Serbian ôs, Lithuanian ašìs, Old Prussian assis, Greek axon-, áxōn, Sanskrit ákṣaḥ, Avestan aša- "armpit"
Note: The Indo-European base *h2eḱs- also has derivatives with a suffixal l, for which see ala, axletree; compare also Welsh echel "axle, pivot," Breton ahel, which may go back to *akselā. The various thematic forms and extensions of h2eḱs- may reflect a root noun rather than an i-stem as in Latin; see E. Hamp, "Refining Indo-European Lexical Entries," Zeitschrift für vergleichende Sprachforschung, 95. Band, 1. Heft (1981), pp. 81-83. The original meaning of the noun may have been "shoulder joint"—if so, Avestan would be the only language to preserve this sense. It has been suggested that *h2eḱs- was formed by a "root extension" -s- from the verbal base *h2eǵ- "drive (cattle, etc.), set in motion (see agent).