nounWord forms: plural -ses (-ˌsiːz)1. printing another name for double dagger
2. musica. (in ancient Greek theory) any interval smaller than a whole tone, esp a semitone in the Pythagorean scale
b. (in modern theory) the discrepancy of pitch in just intonation between an octave and either a succession of four ascending minor thirds (great diesis), or a succession of three ascending major thirds (minor diesis)
Word origin
C16: via Latin from Greek: a quarter tone, literally: a sending through, from
diienai; the double dagger was originally used in musical notation