/ Dictionary / Index B boulder: Meaning and Definition of Find definitions for: boul•der Pronunciation: (bōl'dur), [key] — n. a detached and rounded or worn rock, esp. a large one. Boul•der Pronunciation: (bōl'dur), [key] — n. a city in N Colorado. 76,685. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: boulder (Thesaurus) Boulangism Boulder Canyon Related Content Daily Word Quiz: supine Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language