/ Dictionary / Index U up quark: Meaning and Definition of Find definitions for: up' quark" Pronunciation: [key] — Physics. Physics. the quark having electric charge 2/3 times the elementary charge and strangeness and charm equal to 0. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Uppsala upraise Related Content Daily Word Quiz: fabricate Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language