Sentence:  But through the oligopoly, charcoal fuel proliferated throughout London's trades and industries.  By the 1200s, brewers and bakers, tilemakers, glassblowers, pottery producers, and a range of other craftsmen all became hour-to-hour consumers of <WSD>charcoal</WSD>. 
Meaning of the word marked with <WSD> tags:  Impure carbon obtained by destructive distillation of wood or other organic matter, that is to say, heating it in the absence of oxygen.