Diminutions

Diminutions are a term used in music theory to describe the subdivision of longer note values into a series of shorter notes, producing rhythmic and melodic elaboration. The word derives from Latin diminuere, “to lessen.” In practice, a single long note may be replaced by a group of shorter notes that fits the same rhythmic duration, or a melodic idea may be repeated in a more elaborate, faster version.

Historically, diminutions have two main facets. In Renaissance and early Baroque practice, musicians often supplied diminutions as divisions or ornaments when performing a cantus firmus or a written melody, sometimes improvised and sometimes notated as divisions. These diminutions served decorative and technical purposes, allowing virtuosic display within the constraints of a given meter and tempo. In later Baroque and classical contexts, performers frequently realized figured bass lines and melodic passages by subdividing longer values into shorter notes, a practice that became standard in continuo performance and keyboard or lute music.

In modern musicology, diminution can also refer to a deliberate compositional technique in which a theme is restated with shorter note values, producing a high-velocity variation of the original material. This rhythmic shortening is the counterpart to augmentation, which lengthens note values instead.

Diminution thus encompasses both historical performance practices of ornamenting and subdividing notes and a broader theoretical concept of rhythmic and melodic diversification within a musical work. See also ornament, mordent, trill, and variation.