/ Dictionary / Index P Placentia: Meaning and Definition of Find definitions for: Pla•cen•tia Pronunciation: (plu-sen'shu, -shē-u), [key] — n. a town in S California. 35,041. ancient name of Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. placentation place of arms Related Content Daily Word Quiz: vertigo Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language