Equator
来自Big Physics
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late Middle English: from medieval Latin aequator, in the phrase circulus aequator diei et noctis ‘circle equalizing day and night’, from Latin aequare ‘make equal’ (see equate).
wiktionary
From Late Latin( circulus) aequator ( diei et noctis).
etymonline
equator (n.)
late 14c., from Medieval Latin aequator (diei et noctis) "equalizer (of day and night)," agent noun from Latin aequare "make equal" (see equate). When the sun is on the celestial equator, twice annually, day and night are of equal length. Sense of "celestial equator" is earliest, extension to "terrestrial line midway between the poles" first recorded in English 1610s.
