Mo. Rev. Stat. § 338.210
As used in sections 338.210 to 338.300 "pharmacy" shall mean any pharmacy, drug, chemical store, or apothecary shop, conducted for the purpose of compounding, and dispensing or retailing of any drug, medicine, chemical or poison when used in the compounding of a physician's prescription.
(L. 1951 p. 734 § 1(a))