ostimme

Ostimme is a German term encountered in music theory that designates the outer voices of a polyphonic texture. In four-part writing, the outer voices are typically the soprano (upper) and bass (lower) lines, which frame the harmony and often carry the principal melodic material. The term Ostimme is less standard than Oberstimme (upper voice) and Unterstimme (lower voice); some writers use Ostimme as a variant or synonym for the pair of outer voices, while others reserve it for broader or regional usages. Because of this variability, many texts prefer the clearer terms Oberstimme and Unterstimme.

In practice, the ostimme contrasts with the inner voices, such as the alto and tenor, which occupy the middle range and provide counterpoint. Outer voices tend to have greater melodic prominence, broader range, and stronger cadential emphasis, and they often outline the cantus firmus or primary melodic contour in chorales, fugues, and other polyphonic textures. Analyzing which line constitutes the ostimme helps illuminate voice-leading decisions, thematic architecture, and the hierarchical structure of a piece.

Historically, discussions of outer voices appear in Renaissance and Baroque theory and continue in modern analytic and pedagogical writings. In many contexts, the more precise terms Oberstimme and Unterstimme are preferred, but Ostimme may appear in certain regional traditions or older sources.

See also: Oberstimme, Unterstimme, four-part harmony, counterpoint.