Parallel Supporting Melody (PSM)
Parallel supporting melodies (PSM) are melodies that are similar in contour to a primary melody (a) or secondary melody (b). They often maintain a constant interval relationship with the melody they support.
Static Support (SS)
Static supporting (SS) parts are of two types: (a) sustained tones or chords, which are often pedal tones, and (b) repeated melodic and rhythmic figures or ostinato.