[ad. L. quadrantālis: see QUADRANT sb.1 and -AL.] Having the shape of, consisting of, connected with, a quadrant or quarter-circle; esp. quadrantal arc († arch).
1678. Hobbes, Decam., ad. fin., Wks. 1845, VII. 180. A straight line equal to the quadrantal arc BLD.
1703. T. N., City & C. Purchaser, 14. A Quadrantal Casement, rising from its Plain.
1797. Hellins, in Phil. Trans., LXXXVIII. 529. The length of a quadrantal arch of the circle.
1867. G. Barry, Sir C. Barry, iv. 116. The central building with quadrantal corridors.
1871. B. Stewart, Heat (ed. 2), § 71. A quadrantal arc of a meridian on the earth’s surface.
b. Quadrantal deviation, error, triangle (see quots.).
1706. Phillips (ed. Kersey), Quadrantal Triangle, a Spherick Triangle, that has at least a Quadrant for one of its Sides, and one Angle Right.
1788. Herschel, in Phil. Trans., LXXVIII. 374. We may resolve the quadrantal triangle q c n.
1857. Whewell, Hist. Induct. Sc. (ed. 3), III. 528. The magnetic effect of the iron in a ship may be regarded as producing two kinds of deviation [of a ship’s compass] … a ‘polar-magnet deviation,’… and a quadrantal deviation, which changes from positive to negative as the keel turns from quadrant to quadrant.
1865. Q. Rev., 358. The quadrantal error which depends only on the position of the horizontal soft iron of the ship.
