‖n.; pl.marsupia [ L., a pouch ], (Anat. & Zool.) (a) The pouch, formed by a fold of the skin of the abdomen, in which marsupials carry their young; also, a pouch for similar use in other animals, as certain Crustacea. (b) The pecten in the eye of birds and reptiles. See Pecten. [ 1913 Webster ]