coal vs tar

coal

noun
  • charcoal. 

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

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

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. 

tar

noun
  • Coal tar. 

  • A file produced by such a program. 

  • A black, oily, sticky, viscous substance, consisting mainly of hydrocarbons derived from organic materials such as wood, peat, or coal. 

  • A Persian long-necked, waisted string instrument, shared by many cultures and countries in the Middle East and the Caucasus. 

  • A solid residual byproduct of tobacco smoke. 

  • A single-headed round frame drum originating in North Africa and the Middle East. 

  • Black tar, a form of heroin. 

  • A program for archiving files, common on Unix systems. 

verb
  • To besmirch. 

  • To create a tar archive. 

  • To coat with tar. 

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