octave species

In early Greek music theory, an octave species (εἶδος τοῦ διὰ πασῶν, or σχῆμα τοῦ διὰ πασῶν) is a sequence of incomposite intervals (ditones, minor thirds, whole tones, semitones of various sizes, or quarter tones) making up a complete octave . The concept was also important in Medieval and Renaissance music theory.