Pēr'pen-dī'e'ū-lar1, a.
a. [Lat. perpendicularis, perpendicularis, Fr. perpendiculaire, Pr., Sp., & Pg. perpendicular, It. perpendicolare. See supra.]
- Exactly upright; pointing to the zenith; at right angles to the plane of the horizon; extending in a right line from any point toward the center of the earth.
- (Geom.) At right angles to a given line or surface; as, the line a d is perpendicular to the line b c.