alter vs invaginate

alter

verb
  • To change the form or structure of. 

  • To castrate, neuter or spay (a dog or other animal). 

  • To tailor clothes to make them fit. 

  • To become different. 

  • To affect mentally, as by psychotropic drugs or illness. 

noun
  • An identity or headmate of a person with dissociative identity disorder (previously known as multiple personality disorder). A member of a system. 

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 

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