Definitions
1.verbTo fold up or enclose into a sheath-like or pouch-like structure, either naturally or as part of a surgical procedure.
2.verbTo turn or fold inwardly.
3.verbTo fold inward to create a hollow space where none had existed, as with a gastrula forming from a blastula.
4.adjectiveSheathed
5.adjectiveHaving one portion of a hollow organ drawn back within another portion.