\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[deg] 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.