noun (n)

• intermediate between peat and bituminous coal(noun.substance)

  Synonym:
  brown coal, wood coal
  

  source: wordnet30
• Mineral coal retaining the texture of the wood from which it was formed, and burning with an empyreumatic odor. It is of more recent origin than the anthracite and bituminous coal of the proper coal series. Called also brown coal, wood coal.(noun)

  source: webster1913