Dig"i*ta`lin (?), n. [Cf. F. digitaline.] (a) (Med.) Any one of several extracts of foxglove (Digitalis), as the "French extract," the "German extract," etc., which differ among themselves in composition and properties. (b) (Chem.) A supposedly distinct vegetable principle as the essential ingredient of the extracts. It is a white, crystalline substance, and is regarded as a glucoside.