Incidentally

Origin

incidental + -ly

Full definition of incidentally

Adverb

incidentally

(manner) In an incidental manner; not of central or critical importance.The book discussed the subject, but only incidentally.
By chance; in an unplanned way.
(speech act, conjunctive) Parenthetically, by the way.Incidentally, did you hear anything new from your brother yesterday?

Synonyms

(parenthetically) apropos, as a matter of fact, by the way

Antonyms

(in an incidental manner) inevitably, certainly