sesquialtera

Definition of the Italian term sesquialtera in music:

1. relationship of 3/2 (used in medieval and Renaissance music theory in relation to intervals and note values)
2. organ mixture stop usually of two ranks at 2⅔' and 1⅗' pitch, sounding a twelfth and a seventeenth above the notes played (equivalent to "Sollicinal" in German and "Sesquialtera" in Latin)