The Collaborative International Dictionary
birch camphor
Betulin \Bet"u*lin\, n. [L. betula birch tree.] (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.
--Watts.