any of the principal modes (mode) of the art music of Persian-speaking areas, used as the basis for composition and improvisation. A dastgāh incorporates a scale, a motif, a group of short pieces, and a recognizable identity. The scale (maqām) is a collection of seven pitches, some of which may be temporarily altered, using various combinations of whole tones, semitones, and fractional tones (see microtonal music). The motif is a short four-to-six-note phrase (māyeh), to which musicians repeatedly refer in performance. The short pieces (gūshehs) emphasize different parts of the scale and various tonal relationships. A recognizable musical character is established for each performance.

Ordinarily, 12 dastgāhs are recognized: shūr (the most important) and its four derivatives, dashtī, abu atā, afshāri, and bayāt-e tork; homāyun and its derivative, bayāt-e esfāhān; segāh; chāhārgāh; māhur (which is close to Western major); navā; and rāst-panjgāh. The 12 dastgāhs, with their constituent pieces, make up the radīf, a body of music consisting of 200 to 300 pieces that are memorized and then become the basis of composition and improvisation.

Conceptually and in their musical content, dastgāhs and their constituent gūshehs are related to the Arabic system of maqāmāt and the Turkish makams, and they are almost identical to the mugams of the art music of Azerbaijan. Roughly before 1880, the Persian musical system may have been very close to those of Syria, Egypt, and Iraq; however, in the course of the 20th century, in part because of political and cultural changes, it developed a greater degree of independence.