Per′pen‐dic″u‐lar (?), a. [L. perpendicularis, perpendicularius: cf. F. perpendiculaire. See Perpendicle, Pension.] 1. Exactly upright or vertical; 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.
2. (Geom.) At right angles to a given line or surface; as, the line ad is perpendicular to the line bc.
Perpendicular style(Arch.), a name given to the latest variety of English Gothic architecture, which prevailed from the close of the 14th century to the early part of the 16th; — probably so called from the vertical style of its window mullions.