paction vs settlement agreement

paction

noun
  • A pact, an agreement. 

verb
  • To form a pact; to make a binding agreement. 

settlement agreement

noun
  • A contractual agreement between parties to actual or potential litigation by which each party agrees to a resolution of the underlying dispute. 

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