垂直,直立
Perpendicularity \Per`pen*dic`u*lar"i*ty\, n. [Cf. F. perpendicularit['e].] The quality or state of being perpendicular.
perpendicularity n 1: the relation of opposition between things at right angles [syn: {orthogonality}, {orthogonal opposition}] 2: the quality of being at right angles to a given line or plane (especially the plane of the horizon)