jointure vs unification

jointure

verb
  • To settle a jointure upon. 

noun
  • An estate settled on a wife, which she is to enjoy after her husband's death, for her own life at least, in satisfaction of dower. 

unification

noun
  • Given two terms, their join with respect to a specialisation order. 

  • The act of unifying. 

  • The state of being unified. 

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