Astron. Also 7 colour. [ad. L. colūr-us, Gr. κόλουρος dock-tailed, truncated (f. κόλ-ος docked, curtailed + οὐρά tail), as sb. pl. (αἱ) κόλουροι (sc. γραμμαί) the colures, so called, according to Proclus, because their lower part is permanently cut off from view (i.e., in Greece, or elsewhere away from the equator). So F. colure. Both pronunciations are found in verse.]
Each of two great circles that intersect each other at right angles at the poles, and divide the equinoctial and the ecliptic into four equal parts. One passes through the equinoctial points, the other through the solstitial points, of the ecliptic.
1398. Trevisa, Barth. De P. R., VIII. vii. (Tollem. MS.). And coluri beþ seyde as it were collitauri, and haueþ þat name of þe tayle of a wilde oxe, þat arereþ his tayle and makeþ an imparfite cercle: and colurus is seyde as it were unparfite cerclis.
1549. Compl. Scot., vi. (1872), 50. Ther is tua vthir circlis in the spere callit colures.
1551. Recorde, Cast. Knowl. (1556), 33. Named Colures in greek, that is trunked circles, bycause some partes of them come not into our sighte.
1667. Milton, P. L., IX. 66. From Pole to Pole, traversing each Colure.
1669. Sturmy, Mariner’s Mag., V. 96. Two Colures through the Poles do run, Quartring the Circle of the Sun.
1728. Newton, Chronol. Amended, i. 83. Eudoxus drew the Colure of the Solstices through the middle of the Great Bear.
1819. H. Busk, Vestriad, IV. 22. Her daily tour, Around the ecliptic and across colure.
1854. Moseley, Astron., xxvii. (ed. 4), 113. This plane will intersect … the heavens in a circle called the solstitial colure.
