atonality, in music, systematic avoidance of harmonic or melodic reference to tonal centers (see key). The term is used to designate a method of composition in which the composer has deliberately rejected the principle of tonality. Tonality is a form of musical organization that involves a clear distinction between consonance and dissonance, a definite classification of harmonic results as more and less dissonant, and arrangement of tones in a scale that contains common harmonic and melodic functions and goal points. The gradual rejection of this principle has been apparent since the later 19th cent., when greatly increased use of chromatic harmonies in the music of Liszt, Wagner, and Richard Strauss and the use of nonfunctional harmonies in the music of Debussy almost completely obscured whatever basic tonalities were present in their music.

The abandonment of tonality in the early 20th cent. by Schoenberg, Berg, Webern, Ives, and many other composers was the next logical step in the evolution of musical style. To compensate for this lack of one principle of order, another had to be substituted. The most successful one proposed thus far is that of dodecaphony, or twelve-tone music (see serial music). Atonality is also used by some to designate all music that has discarded the earlier principle of tonality, whether organized in some other way or not. Others use it only for works such as Schoenberg's Pierrot Lunaire, in which notes and harmonies are used in a free, nonsystematic manner. By the close of the 20th cent., atonal music has become a part of the classical repertoire. However, some critics feel that this music's austerity and rigor lessen its expressive potential, and it has failed to attract a large audience.

In music, the absence of functional harmony as a primary structural element. Probably originally a pejorative term applied to music of extreme chromaticism, it has become the most widely used descriptive term for 20th-century music whose connection with tonality is difficult to hear. Arnold Schoenberg and his students Alban Berg and Anton Webern are regarded as the seminal atonal composers; the serialism of their later work is often distinguished from their earlier “free atonality.”

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