trench coat vs winter coat

trench coat

noun
  • A military-style raincoat with a belt and deep pockets and often epaulettes. 

winter coat

noun
  • A warm coat, often an overcoat, fit to be worn in winter 

  • An animal's seasonal appearance in winter, notably thicker and/or otherwise camouflaged plumage or fur after (often autumnal) moulting 

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