letting vs tenancy

letting

noun
  • Synonym of tenancy. 

  • Hyponyms: sublease, underlease, subtenancy, undertenancy, subletting, underletting, (informal) sublet, underlet 

tenancy

noun
  • Synonym of lease (an interest in land, its related contract or the document containing that contract); more commonly used when a lease is short-term or has a periodic rent that is not merely nominal. 

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