outerwear vs trench coat

outerwear

noun
  • Clothing (such as a raincoat) worn over one's clothes when outdoors. 

  • Clothing (such as a dress) worn over one's underwear. 

trench coat

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

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