Culm

Webster's Dictionary of the English Language

·noun Mineral coal that is not bituminous; anthracite, especially when found in small masses.

II. Culm ·noun The stalk or stem of grain and grasses (including the bamboo), jointed and usually hollow.

III. Culm ·noun The waste of the Pennsylvania anthracite mines, consisting of fine coal, dust, ·etc., and used as fuel.