perpendicular

Universal Words adjective, noun adjective 1 ~ (to sth) (usually technical) forming an angle of 90ｰ with another line or surface; upright and going straight up: Are the lines perpendicular to each other? * The staircase was almost perpendicular (= very steep). 2 (Perpendicular) (architecture) connected with a style of architecture common in England in the 14th and 15th centuries, that makes use of vertical lines and wide arches noun (the perpendicular) [sing.] a line, position or direction that is exactly perpendicular: The wall is a little out of the perpendicular.