Pn. the 16th letter of the Roman alphabet Pn. a multivalent nonmetallic element of the nitrogen family that occurs commonly in inorganic phosphate rocks and as organic phosphates in all living cells; is highly reactive and occurs in several allotropic forms p-n junctionn. the junction between a p-type semiconductor and an n-type semiconductor p-n-p transistorn. a junction transistor having an n-type semiconductor between a p-type semiconductor that serves as an emitter and a p-type semiconductor that serves as a collector p-type semiconductorn. a semiconductor in which electrical conduction is due chiefly to the movement of positive holes P. G. Wodehousen. English writer known for his humorous novels and stories (1881-1975) P. P. von Mausern. German arms manufacturer and inventor of a repeating rifle and pistol (1838-1914) P. T. Barnumn. United States showman who popularized the circus (1810-1891) p.a.adv. by the year; every year (usually with reference to a sum of money paid or received) P.A.n. an electronic amplification system used as a communication system in public areas P.A. systemn. an electronic amplification system used as a communication system in public areas P.E.n. the mechanical energy that a body has by virtue of its position; stored energy p.m.adj. after noon P.M.adv. between noon and midnight P.O.n. a noncommissioned officer in the Navy or Coast Guard with a rank comparable to sergeant in the Army
