Diminution

Diminution is the act or process of becoming smaller or less, or the thing that results from such a reduction. In general use, it denotes a decrease in size, amount, degree, or importance. The word derives from Latin diminutio, through Old French diminucion.

In music theory, diminution refers to a technique in which a melodic theme or subject is presented in shorter rhythmic values than its original form, often subdividing longer notes into smaller notes. It is a common device in Renaissance and Baroque contrapuntal writing and is often contrasted with augmentation, which lengthens the note values. Diminution can occur within a single line or as part of variation and is sometimes employed in canons and fugues to develop a theme.

In linguistics, diminution is used to describe the formation or use of diminutives—forms that convey small size, affection, or familiarity. Diminutive forms are created by affixes, reduplication, or phonological changes depending on the language, and can affect nouns, adjectives, or even verbs.

In broader contexts, diminution simply marks a reduction in any measurable aspect, such as quantity, intensity, or numerical value. The term is sometimes used in fields like economics, medicine, and optics to denote decreases, though those uses are typically described with more specific terms. Diminution should not be confused with augmentation, which denotes growth or increase.