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.
〔蒋〕[equ相等，-ator表示物；“均分地球为南北两半球的纬线”] 赤道
〔李〕[equat(e) v.使相等；-or n.=thing表示物→“line that equates等分线”→] n. the great circle of the earth which equates the distance between the poles 赤道（地球上等分经线的纬线）▽equatorial [equator;-ial a.] a.赤道的