/ Dictionary / Index B bottom quark: Meaning and Definition of Find definitions for: bot'tom quark" Pronunciation: [key] — Physics. Physics. the quark having electric charge −1/3 times the elementary charge and bottom quantum number −1. It is more massive than the up, down, strange, and charmed quarks. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. bottom-of-the-line bottom round Related Content Daily Word Quiz: sinister Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language