1. Regarding how something is casual, unimportant, or not remarkably significant: Mr. Thorpe was an outstanding lawyer, and incidentally, he was also a singer performing with the local operetta society.

The government report discussed the spying problem only incidentally.

2. Conveying how an introduction or a statement provides added information or includes another topic: Oliver recently met his friend's wife, who incidentally was a well-known reporter on TV.

Incidentally, Corinne saw Rebecca today who said that she recently got a job with a publisher as an editor.