protectorship vs shelter

protectorship

noun
  • The office of a protector or regent; protectorate. 

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