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1. An imaginary line around the Earth forming the great circle that is equidistant from the north and south poles
   "the equator is the boundary between the northern and southern hemispheres"
    
2. A circle dividing a sphere or other surface into two usually equal and symmetrical parts

Derived forms: equators

See also: equate, equatorial, equinoctial

Type of: circle, great circle

Encyclopedia: Equator