coal vs slate

coal

noun
  • A black or brownish black rock formed from prehistoric plant remains, composed largely of carbon and burned as a fuel. 

  • A type of coal, such as bituminous, anthracite, or lignite, and grades and varieties thereof, as a fuel commodity ready to buy and burn. 

  • A glowing or charred piece of coal, wood, or other solid fuel. 

  • A piece of coal used for burning (this use is less common in American English) 

  • charcoal. 

verb
  • To supply with coal. 

  • To take on a supply of coal (usually of steam ships). 

  • To burn to charcoal; to char. 

  • To mark or delineate with charcoal. 

  • To be converted to charcoal. 

slate

noun
  • A fine-grained homogeneous sedimentary rock composed of clay or volcanic ash which has been metamorphosed so that it cleaves easily into thin layers. 

  • An artificial material resembling slate and used for the same purposes. 

  • A list of affiliated candidates for an election. 

  • A record of money owed. 

  • A tablet computer. 

  • A thin plate of any material; a flake. 

  • The bluish-grey colour of most slate. 

  • A chalkboard, sheet of slate for writing on with chalk or with a thin rod of slate (a slate pencil) formerly commonly used by both students and teachers in schools. 

  • A roofing-tile made of slate. 

verb
  • To cover with slate. 

  • To schedule. 

  • To criticise harshly. 

  • To set a dog upon (a person). 

  • To anticipate or strongly expect. 

  • To nominate, appoint, or designate. 

adj
  • Having the bluish-grey/gray colour of slate. 

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