ostium
noun
os·ti·um ˈä-stē-əm 
plural ostia ˈä-stē-ə
: a mouthlike opening in a bodily part (such as a fallopian tube or a blood vessel)
Word History
Etymology
New Latin, from Latin, door, mouth of a river; akin to Latin os mouth — more at oral
First Known Use
1683, in the meaning defined above
Medical Definition
ostium
noun
os·ti·um ˈäs-tē-əm
plural ostia -tē-ə
: a mouthlike opening in a bodily part (as a fallopian tube or a blood vessel)
stenosis of coronary ostia
R. L. Cecil & R. F. Loeb
R. L. Cecil & R. F. Loeb