arbor vs shelter

arbor

noun
  • A shady sitting place or pergola usually in a park or garden, surrounded by climbing shrubs, vines or other vegetation. 

  • A grove of trees. 

  • A spindle of a wheel. 

  • A bar for supporting cutting tools. 

  • An axis or shaft supporting a rotating part on a lathe. 

shelter

noun
  • A refuge, haven or other cover or protection from something. 

  • An institution that provides temporary housing for homeless people, battered women, etc. 

verb
  • To take cover. 

  • To provide cover from damage or harassment; to shield; to protect. 

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