Breadcrumb Home > Dictionary > Index P placid: Meaning and Definition of Find definitions for: plac•id Pronunciation: (plas'id), [key] — adj. pleasantly calm or peaceful; unruffled; tranquil; serenely quiet or undisturbed: placid waters. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: placid (Thesaurus) placet Plácido's disk ✖ Related Content Daily Word Quiz: umbrage Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language