/ Dictionary / Index C coincidental: Meaning and Definition of Find definitions for: co•in•ci•den•tal Pronunciation: (kō-in"si-den'tl), [key] — adj. happening by or resulting from coincidence; by chance: a coincidental meeting. existing or occurring at the same time. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: coincidental (Thesaurus) coincident coincident indicator Related Content Daily Word Quiz: panacea Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language