Definition from Wiktionary, the free dictionary
- high quality coal
(Can we date this quote?) Walter Hines Page, Arthur Wilson Page, The World's work, Volume 38:
- The drop in 1918 was also a fall in the production of black coal. In other words he losses were in the best coal, the gains in the poorer coal
- (non technical) coal
high quality coal
When used in comparison to brown coal or other grades of coal, the specific definition is likely intended. When used in comparison to white coal, or in a non-technical sense, it may mean any type of coal.