/ Dictionary / Index B brilliancy: Meaning and Definition of Find definitions for: bril•lian•cy Pronunciation: (bril'yun-sē), [key] — pl. -cies an instance of brilliance: the brilliancies of Congreve's wit. brilliance. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: brilliancy (Thesaurus) brilliance brilliant 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