gazebo vs shelter

gazebo

noun
  • A belvedere, either a type of summer-house or a roofed, detached porch-like structure, usually in a yard, park or lawn. 

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 gazebo and shelter occurred in a corpus of books? (source: Google Ngram Viewer )