|1.||occurring by chance, unexpectedly, or unintentionally|
|3.||music denoting sharps, flats, or naturals that are not in the key signature of a piece|
|4.||logic (of a property) not essential; contingent|
|5.||an incidental, nonessential, or supplementary circumstance, factor, or attribute|
|6.||music a symbol denoting a sharp, flat, or natural that is not a part of the key signature|
in music, sign placed immediately to the left of (or above) a note to show that the note must be changed in pitch. A sharp () raises a note by a semitone; a flat () lowers it by a semitone; a natural () restores it to the original pitch. Double sharps () and double flats () indicate that the note is raised or lowered by two semitones. Sharps or flats that are placed at the beginning of a musical staff, called a key signature, indicate the tonality, or key, of the music and are not considered accidentals.
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