What is "sesquialtera"

Sesquialter \Ses`qui*al"ter\, Sesquialtera \Ses`qui*al"ter*a\, n. [NL. sesquialtera.] (Mus.) A stop on the organ, containing several ranks of pipes which re["e]nforce some of the high harmonics of the ground tone, and make the sound more brilliant.

n. 1 (context music English) A ratio of 3:2. 2 (context music English) An organ stop that uses two ranks of different pipes.

Sesquialtera is an organ stop of principal scale comprising ranks at 2' and 1'.

Sesquialtera is a genus of moth in the family Geometridae.

Sesquialtera may refer to:

• Sesquialtera (moth), a genus of moth in the family Geometridae
• Sesquialtera (organ stop)
• Sesquialterum in mathematics, the ratio 3:2, a superparticular ratio
  • Hemiola, the ratio 3:2 as used in medieval music theory