Definition of invaginated:
(adj) :
(biology) Having one portion of a hollow organ drawn back within another portion.
(v) :
(medicine, surgery) To fold up or enclose into a sheath-like or pouch-like structure, either naturally or as part of a surgical procedure.
(v) :
(medicine) To fold inward to create a hollow space where none had existed, as with a gastrula forming from a blastula.
(v) :
(medicine) To turn or fold inwardly.
(adj) :
(biology) sheathed