/ Dictionary / Index P particle velocity: Meaning and Definition of Find definitions for: par'ticle veloc"ity Pronunciation: [key] — Physics. Physics. the velocity of a point in a medium that is undergoing wave motion. Cf. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. particle physics parti-colored Related Content Daily Word Quiz: careening Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language