any fossil plant of the genus Calamites and related genera of the Carboniferous Period, resembling oversized horsetails and constituting much of the coal used as fuel.
Origin: 1745–55; < NL Calamites the genus name, L calamītēs < Gk kalamtēs reedlike. See calamus, -ite1
cal·a·mite (kāl'ə-mīt') n. Any of various extinct, chiefly carboniferous trees of the genus Calamites, related to the modern-day herbaceous horsetails (Equisetum).
[New Latin Calamītēs, genus name, from Late Greek kalamītēs, reedlike, from Greek kalamos, reed.]