accidental: Meaning and Definition of

ac•ci•den•tal

1. happening by chance or accident; not planned; unexpected: an accidental meeting.
2. nonessential; incidental; subsidiary: accidental benefits.
3. relating to or indicating sharps, flats, or naturals.

1. a nonessential or subsidiary circumstance, characteristic, or feature.
2. a sign placed before a note indicating a chromatic alteration of its pitch.