From Biology-Online Dictionary | Biology-Online Dictionary


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. (Science: geometry) at right angles to a given line or surface; as, the line ad is perpendicular to the line bc. Perpendicular style, 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.

Origin: L. Perpendicularis, perpendicularius: cf. F. Perpendiculaire. See Perpendicle, Pension.

1. A line at right angles to the plane of the horizon; a vertical line or direction.

2. (Science: geometry) A line or plane falling at right angles on another line or surface, or making equal angles with it on each side.