onrush vs shelter

onrush

noun
  • An aggressive assault. 

  • A forceful rush or flow forward. 

verb
  • To assault aggressively. 

  • To rush or flow forward forcefully. 

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