coal vs ebony

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. 

ebony

noun
  • A deep, dark black colour. 

  • A black key on a piano or other keyboard instrument. 

  • A tree that yields such wood. 

  • A hard, dense, deep black wood from various subtropical and tropical trees, especially of the genus Diospyros. 

adj
  • Made of ebony wood. 

  • Dark-skinned; black; especially in reference to African-Americans. 

  • A deep, dark black colour. 

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