equator
UK /ɪˈkweɪ.tə/ · US /ɪˈkweɪ.tɚ/ noun, proper noun
Forms equators aequator æquator equatour
- noun (geography, often “the Equator”) An imaginary great circle around Earth, equidistant from the two poles, and dividing earth's surface into the northern and southern hemispheres.
- noun (astronomy) A similar great circle on any sphere, especially on a celestial body, or on another reasonably symmetrical three-dimensional body.
- noun The midline of any generally spherical object, such as a fruit or vegetable, that has identifiable poles. “Slice the onion through the equator.”
- noun The celestial equator.
- proper noun (geography) Earth’s equator.
Etymology
From Late Latin (circulus) aequator (diei et noctis).
Webster’s 1913
- noun The imaginary great circle on the earth's surface, everywhere equally distant from the two poles, and dividing the earth's surface into two hemispheres.
- noun The great circle of the celestial sphere, coincident with the plane of the earth's equator; --so called because when the sun is in it, the days and nights are of equal length; hence called also the equinoctial, and on maps, globes, etc., the equinoctial line. Equator of the sun or of a planet (Astron.), the great circle whose plane passes through through the center of the body, and is perpendicular to its axis of revolution.
Etymology [L. aequator one who equalizes: cf. F. équateur equator. See Equate.]
Sources: Wiktionary · Webster’s 1913 — from the Wiktionary entry “equator”, CC BY-SA 4.0. Details