in music, stepped arrangement of notes following the classical Greek Ionian mode (though mistaken nomenclature in the 16th century has since caused it to be referred to as the Lydian mode). In a major scale the intervals between successive notes after the first are tone, tone, semitone, tone, tone, tone, semitone. Thus, the major scale of D is D–E–F♯–G–A–B–c♯–d, and the same notes descending.