[adverb] introducing a different topic; "by the way, I won't go to the party" Synonyms:by the way, by the bye
[adverb] in an incidental manner; "these magnificent achievements were only incidentally influenced by Oriental models" Synonyms:accidentally, by chance
[adverb] by the way; "apropos, can you lend me some money for the weekend?" Synonyms:apropos
