decidui

Decidui is a Latin term formed as the masculine plural of deciduus, an adjective meaning “falling off” or “shed.” In English-language science, decidui is rarely used; instead the English adjective deciduous is used to describe organisms or tissues that shed parts seasonally, and the noun decidua refers to the lining of the uterus during pregnancy.

In botanical and ecological contexts, deciduous species shed leaves seasonally, typically in autumn in temperate climates, as a strategy to conserve resources during unfavorable conditions. The Latin concept would historically appear in Latin descriptions to denote groups of deciduous trees or leaves, though modern English texts use deciduous instead of the Latin plural.

In medical anatomy, the term decidua refers to the mucous lining of the uterus during pregnancy. It forms from endometrial tissue and is shed after birth as part of the reproductive process. The root is the same, reflecting the overarching sense of shedding.

Etymologically, deciduus derives from Latin roots meaning “down” and “to fall,” yielding a term that conveys something that falls away or is shed. The form decidui appears mainly in older or Latin-language scholarly works, where it functions as a grammatical plural rather than a current standard English term.

Today, decidui is not a standard term in contemporary English scientific writing and is primarily of historical or Latin-language interest, with deciduous and decidua used for the corresponding concepts in most modern contexts.