perpendicular

/ˌpər-pən-ˈdi-kyə-lər/

Middle English perpendiculer, from Middle French, from Latin perpendicularis, from perpendiculum plumb line, from per- + pendēre to hang

adjective

  1. standing at right angles to the plane of the horizon : exactly, upright

  2. being at right angles to a given line or plane

  3. extremely steep : precipitous

vertical perpendicular plumb mean being at right angles to a base line. vertical suggests a line or direction rising straight upward toward a zenith. perpendicular may stress the straightness of a line making a right angle with any other line, not necessarily a horizontal one.

noun

  1. a line at right angles to a line or plane (as of the horizon)