%vaginat%

v. i. & t. [ imp. & p. p. Evaginated; p. pr. & vb. n. Evaginating. ] To become evaginate; to cause to be evaginate. [ Webster 1913 Suppl. ]

n. [ L. evaginatio an extending, evaginare to unsheathe; e out + vagina sheath. ] 1. The act of unsheathing. [ 1913 Webster ]

2. An outgrowth or protruded part. [ Webster 1913 Suppl. ]

v. t. To insert as in a sheath; to produce intussusception in.

{ } a. (Biol.) (a) Sheathed. (b) Having one portion of a hollow organ drawn back within another portion. [ 1913 Webster ]

n. [ L. pref. in- + vagina sheath. ] [ 1913 Webster ]

1. (Biol.) The condition of an invaginated organ or part. [ 1913 Webster ]

2. The inward movement of the wall of a tissue or cell, to form a cavity; also, the cavity thus formed. [ PJC ]

3. Specifically: (Biol., Embryology) The inward movement of one part of the wall of a blastula, to form a gastrula; the process of gastrulation, in which layers of the ovum are differentiated. [ 1913 Webster +PJC ]

☞ In embolic invagination, one half of the blastosphere is pushed in towards the other half, producing an embryonic form known as a gastrula. -- In epibolic invagination, a phenomenon in the development of some invertebrate ova, the epiblast appears to grow over or around the hypoblast. [ 1913 Webster ]

{ } a. [ See Vagina. ] Invested with, or as if with, a sheath; as, a vaginate stem, or one invested by the tubular base of a leaf. [ 1913 Webster ]