Bet·u·lin n.  Chem. a term originally applied to a substance obtained as a resin or tar by extraction from the outer bark of the common European white birch (Betula alba); now referring to the chemical compound (C30H50O2) having a cyclopentanophenanthrene ring system, which is the main constituent of that extract, and which may be obtained crystalline; -- called also birch camphor.

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