perpendicular, adj. & n.
1 a at right angles to the plane of the horizon. b (usu. foll. by to) Geom. at right angles (to a given line, plane, or surface).
2 upright, vertical.
3 (of a slope etc.) very steep.
4 (Perpendicular) Archit. of the third stage of English Gothic (15th-16th c.) with vertical tracery in large windows.
5 joc. in a standing position.
1 a perpendicular line.
2 a plumb-rule or a similar instrument.
3 (prec. by the) a perpendicular line or direction (is out of the perpendicular).
perpendicularity n. perpendicularly adv.
ME f. L perpendicularis f. perpendiculum plumb-line f. PER- + pendere hang
air line, axis, azimuth circle, beeline, chord, diagonal, diameter, direct line, directrix, edge, erect, great-circle course, normal, orthodiagonal, orthogonal, orthometric, plumb, plunging, precipitous, radius, radius vector, rectangular, right angle, right line, right-angle, right-angled, right-angular, secant, segment, sheer, shortcut, side, stand-up, steep, straight, straight course, straight line, straight stretch, straight-up, straight-up-and-down, straightaway, streamline, tangent, transversal, up-and-down, upright, vector, vertical, vertical circle
verticality, erectness, perpendicularity, right angle, normal, azimuth circle, wall, precipice, cliff, elevation, erection, square, plumb line, plummet, vertical, upright, erect, perpendicular
, plumb, normal, straight, bolt, upright, rampant, standing up, rectangular, orthogonal, vertically, up, on end, up on end, right on end, a plomb, endwise, one one's legs, at right angles.
perpendicularity, orthogonality, verticality, orthogonal, perpendicular
, rectangular, uncorrelated.