/ Dictionary / Index R relativistic quantum mechanics: Meaning and Definition of Find definitions for: rel'ativis'tic quan'tum mechan'ics Pronunciation: [key] — Physics. Physics. quantum mechanics based on a wave equation satisfying the mathematical requirements of the special theory of relativity and applying to particles of any velocity. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. relativistic mass relativity Related Content Daily Word Quiz: placid Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language