What are accidentals in piano theory?
In music, an accidental is a note of a pitch (or pitch class) that is not a member of the scale or mode indicated by the most recently applied key signature. In musical notation, the sharp (♯), flat (♭), and natural (♮) symbols, among others, mark such notes—and those symbols are also called accidentals.
What is an example of an accidental in music?
Accidentals can be sharp, flat, or natural notes depending on the context of the key. For example, if we're in the key signature of G major which features the notes G, A, B, C, D, E and F#, any use of an F natural note would be considered to be an accidental.