1560s, from French équidistant (14c.), from Late Latin aequidistantem (nominative aequidistans), from aequi- (see equal (adj.)) + distans (see distant). In reference to a type of map projection, from 1866. Related: Equidistance.
equatorial
equerry
equestrian
equi-
equiangular
equidistant
equilateral
equilibrium
equine
equinox
equip