Definitionen
1.NounThe difference between two quantities or lengths commensurable only in power, as between 1 and the square root of 2, or between the diagonal and side of a square.
2.NounThe remaining part of a whole tone after a minor second has been deducted from it; an augmented unison. Most commonly used to refer to the Pythagorean chromatic semitone, which has a ratio of 2187/2048.
3.NounA distinct division of an insect which is divided from the other divisions by a pinch point.