invaginate vs set back

invaginate

verb
  • To turn or fold inwardly. 

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

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

adj
  • Having one portion of a hollow organ drawn back within another portion. 

  • sheathed 

set back

verb
  • To reverse, go backwards. 

  • To remove from or allow distance. 

  • To delay or obstruct. 

  • To install or position behind a boundary or surface, or in a recess. 

  • To cost money. 

How often have the words invaginate and set back occurred in a corpus of books? (source: Google Ngram Viewer )