In music, accidentals are signs of chromatic alteration of notes, differing from the key signature in applying only to particular notes, and not extending their effect beyond the bar in which they occur. The only exception to this is if an accidental is attached to the last note of the bar and this note is tied to a note in the next bar; in this case the accidental holds good for the latter note also. In some modern atonal music any accidental occurring is understood to affect merely the note before which it is placed, as was often the case in earlier music. Accidentals indicate a temporary change of key.

 

 

There are five different accidentals: the sharp (♯) and double sharp (see illustration), which raise the note to which they are prefixed a semitone and a tone respectively; the flat (♭) and double flat, which lower it correspondingly; and the natural, which cancels the effect of preceding sharps or flats, whether accidental or in the key signature.

 

The names of the accidentals in different languages are shown in the table below. Due to some irregularities in the German names, theses have been set out in full.