oilskin vs waterproof

oilskin

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

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

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

waterproof

noun
  • Cloth made waterproof, or any article made of such cloth, or of other waterproof material, as rubber; especially, an outer garment made of such material. 

  • A substance or preparation for rendering cloth, leather, etc., impervious to water. 

verb
  • To make waterproof or water-resistant. 

adj
  • Incapable of failing; unassailable. 

  • Resistant to the effects of water. 

  • Made of or covered with material that doesn't allow water in. 

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