annex vs mansion

annex

verb
  • To attach or connect, as a consequence, condition, etc. 

  • To join; to be united. 

  • To add something to another thing, especially territory; to incorporate. 

noun
  • An appendix to a book or document. 

  • An addition to the territory of a country or state, from a neighbouring country or state, normally by military force. 

  • An addition, an extension. 

  • An addition or extension to a building. 

mansion

noun
  • An astrological house; a station of the moon. 

  • An apartment building. 

  • One of twenty-eight sections of the sky. 

  • An individual habitation or apartment within a large house or group of buildings. (Now chiefly in allusion to John 14:2.) 

  • Any of the branches of the Rastafari movement. 

  • A large house or building, usually built for the wealthy. 

  • A luxurious flat (apartment). 

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