- apart or aside from the main subject of attention, discussion, etc.; by the way; parenthetically: Incidentally, while you were waiting for the officer to run your registration through the system, did you notice if the post office was open?
- in the course of something else, and not intentionally:The bone fractures were discovered only incidentally, during an unrelated CT scan of her chest.
- as a subordinate or chance occurrence
- by the way
