adverse possession vs usucapion

adverse possession

noun
  • A means of acquiring title to another's real property without compensation by occupying the property in a manner that has under common law the requirements of being actual, open and notorious, exclusive, hostile, under cover of claim or right, and continuous for a certain number of years. 

usucapion

noun
  • The acquisition of right or title to an object by means of the passage of time. The common law analogue is adverse possession. 

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