/ Dictionary / Index P protozoon: Meaning and Definition of Find definitions for: pro•to•zo•on Pronunciation: (prō"tu-zō'on, -un), [key] — pl. -zo•a protozoan. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: protozoon (Thesaurus) protozoan protract Related Content Daily Word Quiz: acquiesce Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language