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