the THORN-APPLE, in botany, a genus of the pentandria monogynia clas. The corolla is plaited and tunnel-shaped; the calyx is tubulous, angular, and deciduous; and the capsule consists of four valves. There are six species, all natives of warm climates. The thorn-apple is a narcotic poison: It has lately been recommended in cases of madness by Dr Stork, but without answering any useful purpose.