invaginated

/IH0 N V AE1 JH AH0 N EY0 T AH0 D/
verb
  1. 1

    To fold up or enclose into a sheath-like or pouch-like structure, either naturally or as part of a surgical procedure.

  2. 2

    To turn or fold inwardly.

  3. 3

    To fold inward to create a hollow space where none had existed, as with a gastrula forming from a blastula.

Source: https://en.wiktionary.org/wiki/invaginate, https://en.wiktionary.org/wiki/invaginated