/ Dictionary / Index B bull wheel: Meaning and Definition of Find definitions for: bull' wheel" Pronunciation: [key] — Mach. Mach. any large driving gear among smaller gears. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. bullwhacker bullwhip Related Content Daily Word Quiz: secular Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language