the notional circle around the earth that is equidistant at all points from the two poles and divides the earth's surface into the northern and southern hemispheres
= celestial equator
a circle or circular band dividing the surface of a body into two usu equal and symmetrical parts, sometimes imaginary
the equator of a dividing cell
[Middle English from late Latin aequator, from circulus aequator diei et noctis circle that equalizes day and night]