va·gi·na 
(və-jīnə)
(və-jīnə)n. pl. va·gi·nas or va·gi·nae (-nē)
1. Anatomy
a. The passage leading from the opening of the vulva to the cervix of the uterus in female mammals.
b. A similar part in some invertebrates.
2. Biology Any of various sheathlike structures.
[Latin vāgīna, sheath.]