Pentachord

A pentachord in music theory may be either of two things. In pitch-class set theory, a pentachord is defined as any five pitch classes, regarded as an unordered collection (Roeder 2001). In other contexts, a pentachord may be any consecutive five-note section of a diatonic scale (Latham 2002). A pentad is a five-note chord (Bailey 1991, 450).