plant of the group of the pulse family, 1670s, from French légume (16c.), from Latin legumen "pulse, leguminous plant," of unknown origin. One suggestion ties it to Latin legere "to gather" (see lecture (n.)), because they can be scooped by the handful. Used in Middle English in the Latin form legumen (late 14c.).
Any of a large number of eudicot plants belonging to the family Fabaceae (or Leguminosae). Their characteristic fruit is a seed pod. Legumes live in a symbiotic relationship with bacteria in structures called nodules on their roots. These bacteria are able to take nitrogen from the air, which is in a form that plants cannot use, and convert it into compounds that the plants can use. Many legumes are widely cultivated for food, as fodder for livestock, and as a means of improving the nitrogen content of soils. Beans, peas, clover, alfalfa, locust trees, and acacia trees are all legumes.