Diminution is a formal word that refers to the act or process of becoming less.

// The company is committed to seeing that efforts to scale up production do not result in a diminution of quality.

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“A sense of abasement hovers over the performer of the Super Bowl halftime show. It is slight, but it is there. ... The gig—a live gig—is essentially done for free. It ends, the performer is spirited away, and the multi-million-dollar commercials and multi-million-dollar game resume. It’s popular music as the doula to football. The next morning, everyone makes big talk about history and legend-making; the feeling of diminution lingers.” — Doreen St. Félix, The New Yorker, 10 Feb. 2025

In his late 14th century tragic poem Troilus and Criseyde, Geoffrey Chaucer employed the word diminution, contrasting the verb encrece (“increase”) with the phrase “maken dyminucion” (“make diminution”). Like many words Chaucer used, diminution came to English from Anglo-French, and ultimately from the Latin word deminuere, meaning “to diminish,” which is also an ancestor of the English verb diminish. That word entered the language in the 15th century, and the related noun diminishment, a synonym of diminution, was adopted in the 16th century.