Co*lure" (?), n.; pl. Colures (#). [F. colure, L. coluri, pl., fr. Gr. ko`loyros dock-tailed, a"i ko`loyroi (sc. grammai` lines) the colures; fr. ko`los docked, stunted + o'yra` tail. So named because a part is always beneath the horizon.] (Astron. & Geog.) One of two great circles intersecting at right angles in the poles of the equator. One of them passes through the equinoctial points, and hence is denominated the equinoctial colure; the other intersects the equator at the distance of 90° from the former, and is called the solstitial colure.

Thrice the equinoctial line
He circled; four times crossed the car of night
From pole to pole, traversing each colure.
Milton.