What does "culm" mean?

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

Additional senses

  1. 2.(a) Mineral coal that is not bituminous; anthracite, especially when found in small masses. (b) The waste of the Pennsylvania anthracite mines, consisting of fine coal, dust, etc., and used as fuel. Raymond.

Sources