/ Dictionary / Index P Plácido's disk: Meaning and Definition of Find definitions for: Plá'ci•do's disk' Pronunciation: (plä'si-dōz"), [key] — Ophthalm. Ophthalm. a device marked with concentric black rings, used to detect corneal irregularities. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. placid Placidyl Related Content Daily Word Quiz: cur Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language