senna, n. [Cf. It. & Sp. sena, Pg. sene, F. séné; all fr. Ar. sanā.].
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The leaves of several leguminous plants of the genus Cassia. (C. acutifolia, C. angustifolia, etc.). They constitute a valuable but nauseous cathartic medicine. [1913 Webster]
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The plants themselves, native to the East, but now cultivated largely in the south of Europe and in the West Indies. [1913 Webster]
Bladder senna. (Bot.) See under Bladder. -- Wild senna (Bot.), the Cassia Marilandica, growing in the United States, the leaves of which are used medicinally, like those of the officinal senna.