Any plant belonging to the family Fabaceae (commonly known as the pea or bean family), or the fruit or seed of such a plant. Many edible crops are legumes including peas, beans, soybeans, chickpeas, peanuts, and lentils. Edible legumes harvested for their dried seeds are also known as pulses. Some forage crops like clovers and alfalfa are also legumes.

Legumes are of further agricultural importance as the majority form root nodules containing symbiotic (mutualistic) nitrogen-fixing bacteria. Thus, they naturally add nitrogen to the soil and so play a key role in crop rotation and are often used as green manure (particularly clover). Other plants do form such mutualistic relationships with nitrogen-fixing bacteria, but on far smaller scale. Thus, in agricultural contexts, including legumes in rotations often replaces the role of mineral nitrogen fertiliser.