/ Dictionary / Index P particle physics: Meaning and Definition of Find definitions for: par'ticle phys"ics Pronunciation: [key] the branch of physics that deals with the properties and behavior of elementary particles. Cf. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. particle board particle velocity Related Content Daily Word Quiz: fervor Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language