posterius

Posterius is a Latin adjective meaning "coming after" or "posterior." It is the neuter singular form of the adjective posterus, and in Latin the word occurs in phrases describing position, sequence, or orientation. In classical Latin, posterius is used in constructions such as pars posterius ("the latter part") or facies posterius ("the posterior face"), where it indicates the rear or following part of something.

The term is most often encountered today in scientific and scholarly contexts as part of Latin phrases within anatomy, zoology, and botany. In anatomy and morphology, posterius appears in compound terms to denote a posterior aspect, for example in facies posterius or pars posterius. In taxonomic descriptions, posterius may serve as a Latin specific epithet to mark a posterior feature or position when two related taxa are contrasted, though its use as a stand-alone label is rare.

In English-language science writing, posterius is typically left untranslated when used as part of a Latin phrase; otherwise the corresponding English adjective "posterior" is used. The word is distinct from posterus or posterior, which are related forms in Latin and English, respectively.

See also: posterior, posterus, posteriori.