In other words, it is a unison where one note has been altered by a half-step, such as B and B or C and C. The interval is often described as a chromatic semitone. The term, in its French form unisson superflu, appears to have been coined by Jean-Philippe Rameau in 1722, who also called this interval a minor semitone (semiton mineur).
A unison is described as an harmony where one note has been altered by a half-step, such as B and B or C and C. This interval is commonly known as a chromatic semitone. The term "unisson superflu" was introduced by Jean-Philippe Rameau in 1722, who also referred to it as a minor semitone (semiton mineur).