jack bean the best-known name for a group of closely related beans which are now cultivated throughout the tropics. The principal species are Canavalia ensiformis (a New World plant) and C. gladiata (from the Old World). Strictly speaking, the former is jack bean or horse bean and the latter is sword bean, but in practice the names are intermingled and there is little difference between the two species. Both the botanical species names mean ‘swordlike’, a fair description of the long, flat pods.
