Entry 2 senses · 2 variants Webster, 1913 Invaginate · In·vag·i·nate · IPA v. t. a. 01 v. t. To insert as in a sheath; to produce intussusception in. 1. To insert as in a sheath; to produce intussusception in. 02 a. Sheathed. 1. Sheathed.(Biol.)