/ Dictionary / Index I incidentally: Meaning and Definition of Find definitions for: in•ci•den•tal•ly Pronunciation: (in"si-den'tl-ē or, for 1, -dent'lē), [key] — adv. apart or aside from the main subject of attention, discussion, etc.; by the way; parenthetically. in an incidental manner. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: incidentally (Thesaurus) incidental incidental music Related Content Daily Word Quiz: acquiesce Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language