Plácido's disk: Meaning and Definition of

Plá'ci•do's disk'

Pronunciation: (plä'si-dōz"), [key]
— Ophthalm. Ophthalm.
  1. a device marked with concentric black rings, used to detect corneal irregularities.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.