Quarter-tone (Fr. quart de ton; Ger. Viertelton; It. quarto di tono)
- Julian Rushton
An interval half the size of a semitone. The term was used by some 17th- and 18th-century theorists to denote the distance between a sharp and enharmonically distinct flat in mean-tone temperaments (e.g. D♯–E♭). In most contexts, however, it refers to an interval of 1...