Main Entry: os·ti·um

Pronunciation: \ˈäs-tē-əm\

Function: noun

Inflected Form(s): plural os·tia \-tē-ə\

Etymology: New Latin, from Latin, door, mouth of a river; akin to Latin os mouth — more at oral

Date: 1828

: a mouthlike opening in a bodily part (as a fallopian tube or a blood vessel)