Sesquialtera

Sesquialtera ('one and a half') may refer to:


 * Sesquialterum in mathematics, the ratio 3:2, a superparticular ratio
 * Sesquialtera or the equivalent Greek term hemiola, three in the time of two as variously used in music theory:
 * Sesquialtera commonly describes a tempo proportion in mensural notation
 * Hemiola is more common for the temporary substitution of a 2+2+2 musical meter for 3+3
 * Sesquialtera (organ stop), combining mutation ranks at 2$2/3$' and 1$3/5$', i.e. both 3:2 and 5:4 pitch ratios
 * Sesquialtera (moth), a genus of moth in the family Geometridae