| perpendicular | 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. <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. <geometry> A line or plane falling at right angles on another line or surface, or making equal angles with it on each side. Source: Websters Dictionary (01 Mar 1998) |
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| perpendicular fasciculus | A bundle of association fibres running vertically and interconnecting regions of the temporal, occipital, and parietal lobes. (05 Mar 2000) |
| perpendicular plate | Flat portion of a bone which lies within or closely approximates a vertical plane. See: perpendicular plate of ethmoid bone, perpendicular plate of palatine bone. Synonym: lamina perpendicularis, pars perpendicularis, vertical plate. (05 Mar 2000) |
| perpendicular plate of ethmoid bone | A thin plate of bone projecting downward from the crista galli of the ethmoid; it forms part of the nasal septum. Synonym: lamina perpendicularis ossis ethmoidalis. (05 Mar 2000) |
| perpendicular plate of palatine bone | The part of the palatine bone that extends vertically upward from the horizontal lamina; it forms part of the lateral wall of the nasal cavity. Synonym: lamina perpendicularis ossis palatini. (05 Mar 2000) |
| perpetual arrhythmia | An obsolete term for atrial fibrillation. (05 Mar 2000) |
| perpetually growing tooth | A physiologic phenomenon whereby the tooth continually or constantly grows, calcifies, and erupts; e.g., the rat incisor tooth. Synonym: persistently growing tooth. (05 Mar 2000) |
| perphenazine | <drug> This prescription drug is used to treat psychotic disorders and to control nausea/vomiting in adults. It may cause tardive dyskinesia in some patients and can have adverse reactions with other medications. It can cause a wide range of side effects. (09 Oct 1997) |