1. (adverb)by the way, by the bye, incidentally, apropos introducing a different topic; in point of fact Synonyms: incidentally, by the bye, well-timed, accidentally, timely, apropos, by the way, seasonably
2. (adverb)incidentally, accidentally of a minor or subordinate nature Synonyms: incidentally, unintentionally, by the bye, by chance, accidentally, circumstantially, apropos, by the way, unexpectedly