C♯ (C-sharp) is a musical note lying a chromatic semitone above C and a diatonic semitone below D; it is the second semitone of the solfège. C-sharp is thus enharmonic to Dâ™. It is the second semitone in the French solfège and is known there as do dièse. In some European notations, it is known as Cis. In equal temperament it is also enharmonic...
