incidentally

adverb4

1. •
   In an incidental manner.
2. •
   Parenthetically, by the way.

   • Incidentally, did you hear anything new from your brother yesterday?
3. •
   Not of central or critical importance.

   • The book discussed the subject, but only incidentally.
4. •
   By happenstance; in a particular case which has little to no bearing on, and little to no causal relation to, any other case.