/ Dictionary / Index T top quark: Meaning and Definition of Find definitions for: top' quark" Pronunciation: [key] — Physics. Physics. a heavy quark having electric charge 2/3 times the elementary charge. Also called t quark, truth quark. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. topple toprail Related Content Daily Word Quiz: soporific Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language