/ Dictionary / Index P pneumocystis pneumonia: Meaning and Definition of Find definitions for: pneu•mo•cys'tis pneumo'nia Pronunciation: (n"mu-sis'tis, ny"-), [key] — Pathol. Pathol. a pulmonary infection caused by the protozoan Pneumocystis carinii, occurring as an opportunistic disease in persons with impaired immune systems, as AIDS victims. Abbr.: PCP&hasp; Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. pneumoconiosis pneumodynamics Related Content Daily Word Quiz: pugilist Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language