Happening by chance, or unexpectedly; taking place not according to the usual course of things; casual; fortuitous; as, an accidental visit.
- Occurring unexpectedly, unintentionally, or by chance.
- Music Of or relating to an accidental.
- A property, factor, or attribute that is not essential.
- Music Any of various signs that indicate the alteration of a note by one or two semitones or the cancellation of a previous sign.
- Music A note that has been marked with such a sign.