What is 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 called?

codeine — 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. (Webster's 1913.)

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