Codeine \Co"deine\ (k[=o]"d[=e]n or k[-o]*d[=e]"[i^]n), n. [Gr.
kw`deia poppy head: cf. F. cod['e]ine.] (Chem.)
One of the opium alkaloids; a white crystalline substance,
{C18H21NO3}, similar to and regarded as a derivative of
morphine, but much feebler in its action; -- called also
{codeia}.
[1913 Webster]