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.
- Any of various chiefly tropical or subtropical trees, shrubs, or herbs of the genus Cassia in the pea family, having pinnately compound leaves, usually yellow flowers, and long, flat or cylindrical pods.
- A tropical Asian evergreen tree (Cinnamomum cassia) having aromatic bark used as a substitute for cinnamon.
- The bark of this tree.