Definition of: invaginate

(in·vaj′ə·nāt) v. ·nat·ed, ·nat·ing v.t.
1. To put or receive into a sheath.
2. To turn back within itself, as a tubular organ or part.
—v.i.
3. To undergo invagination. [<L in- in + vagina sheath + -ATE²]
—in·vag′i·nat′ed adjective