In music, sharp, or Diese, means higher in pitch. In musical notation, sharp means "higher in pitch by a semitone (half step)," and looks like this:(♯).[1]
Under twelve-tone equal temperament, B sharp, for instance, is enharmonically equivalent to (sounds the same as), C natural, and G sharp is enharmonically equivalent to A flat.
Double sharps also exist; these have the symbol and raise a note by two semitones, or a whole step. Less often there are half or three-quarter sharps.
Although very rare and used only in modern classical music, a triple sharp (♯ ) can sometimes be found. This raises a note by three semitones.
The Circle of fifths tells you how many sharps are in a key signature.
In tuning, sharp can also mean "slightly higher in pitch". If the same note is played on two instruments, and one is slightly higher, it is too sharp compared to the other.
In Unicode, the sharp symbol (♯) is at code point U+266F. Its HTML entity is ♯. The double sharp symbol (𝄪) is at U+1D12A. Some fonts do not show these symbols.