/ Dictionary / Index K kinetic theory of matter: Meaning and Definition of Find definitions for: kinet'ic the'ory of mat'ter Pronunciation: [key] — Physics. Physics. a theory that matter is composed of small particles, all in random motion. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. kinetic theory of heat kinetin 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