ostium

[os-tee-uh m] /ˈɒs ti əm/
noun, plural ostia
[os-tee-uh] /ˈɒs ti ə/ (Show IPA)
1.
Anatomy, Zoology. a small opening or orifice, as at the end of the oviduct.
2.
Zoology. one of the tiny holes in the body of a sponge.
Origin
1655-65; < Latin ōstium entrance, river mouth
British Dictionary definitions for ostium

ostium

/ˈɒstɪəm/
noun (biology) (pl) -tia (-tɪə)
1.
any of the pores in sponges through which water enters the body
2.
any of the openings in the heart of an arthropod through which blood enters
3.
any similar opening
Word Origin
C17: from Latin: door, entrance
ostium in Medicine

ostium os·ti·um (ŏs'tē-əm)
n. pl. os·ti·a (-tē-ə)
A small opening or orifice, as in a body organ.


os'ti·al adj.