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.