Marsupium

n. [Lat., pouch.]

1. (Zoöl.) The pouch in which marsupial animals carry their young.
2. (Med.) A sack or bag with which any part is fomented. Dunglison.

☞ The term is also applied to a muscle in the eye of a hawk, the office of which is to flatten the cornea, enabling the bird to see to a great distance.