/ Dictionary / Index M mercury-vapor lamp: Meaning and Definition of Find definitions for: mer'cu•ry-va•por lamp" Pronunciation: (mûr'kyu-rē-vā"pur), [key] — Elect. Elect. a lamp producing a light with a high actinic and ultraviolet content by means of an electric arc in mercury vapor. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. mercury switch mercy Related Content Daily Word Quiz: cautious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language