oilskin vs overcoat

oilskin

noun
  • A raincoat made from cotton fabric treated with oil and pigment to make it waterproof. 

  • Cloth made from cotton and treated with oil and pigment to make it waterproof. 

  • Foul-weather gear worn by sailors, whether of natural or synthetic materials. 

overcoat

noun
  • A heavy garment worn over other clothes, for protection from cold or weather. 

verb
  • To apply an exterior coating to. 

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