n. [ L. cassia and casia, Gr. kassi`a and kasi`a; of Semitic origin; cf. Heb. qetsīāh, fr. qātsa' to cut off, to peel off. ] 1. (Bot.) A genus of leguminous plants (herbs, shrubs, or trees) of many species, most of which have purgative qualities. The leaves of several species furnish the senna used in medicine. [ 1913 Webster ]

2. The bark of several species of Cinnamomum grown in China, etc.; Chinese cinnamon. It is imported as cassia, but commonly sold as cinnamon, from which it differs more or less in strength and flavor, and the amount of outer bark attached. [ 1913 Webster ]

☞ The medicinal “cassia” (Cassia pulp) is the laxative pulp of the pods of a leguminous tree (Cassia fistula or Pudding-pipe tree), native in the East Indies but naturalized in various tropical countries. [ 1913 Webster ]

Cassia bark, the bark of Cinnamomum cassia, etc. The coarser kinds are called Cassia lignea, and are often used to adulterate true cinnamon. --
Cassia buds, the dried flower buds of several species of cinnamon (Cinnamomum cassia, atc..). --
Cassia oil, oil extracted from cassia bark and cassia buds; -- called also oil of cinnamon. [ 1913 Webster ]