Tone row
![Tone row of Stockhausen's Gruppen für drei Orchester Play the registrally fixed pitches of which correspond with duration units and metronome marks.[2]](/uploads/202502/20/Stockhausen_Gruppen_für_drei_Orchester_series4023.png)
![Principal forms of Webern's tone row from Variations for piano, op. 27. Each hexachord fills in a chromatic fourth, with B as the pivot (end of P1 and beginning of IR8), and thus linked by the prominent tritone in the center of the row Play .[8]](/uploads/202502/20/Webern_-_Piano_Variations_op._27_tone_row4023.png)
![First array of four aggregates (numbered 1–4 at bottom) from Babbitt's Composition for Four Instruments, each vertical line (four trichords labeled a–d) is an aggregate while each horizontal line (four trichords labeled a-d) is also an aggregate[12]](/uploads/202502/20/Array_-_Babbitt's_Composition_for_Four_Instruments4023.png)
![Basic row forms from Stravinsky's Requiem Canticles:[21] P R I IR](/uploads/202502/20/Stravinsky_-_Requiem_Canticles_basic_row_forms4023.png)
In music, a tone row or note row (German:Reihe or Tonreihe), also series and set, refers to a non-repetitive ordering of a set of pitch-classes, typically of the twelve notes in musical set theory of the chromatic scale, though both larger and smaller sets are sometimes found.