Bean is a common name for large plant seeds of several genera of Fabaceae (formerly Leguminosae) used for food or feed. They are also known as legumes.
The term Bean originally referred to the seed of the broad bean, but was later broadened to include members of the genus Phaseolus such as the common bean or haricot and the runner bean and the related genus Vigna. The term is now applied in a general way to many other related plants such as soybeans, peas, lentils, kidney beans, vetches and lupins.
Bean can be used as a near synonym of pulse, an edible legume, though the term "pulses" is usually reserved for leguminous crops harvested for their dry grain. Pulses usually excludes crops mainly used for oil extraction (like soybean and peanut) or those used exclusively for sowing purposes (clover and alfalfa). Leguminous crops harvested green for food, such as snap beans, green peas etc, are classified as vegetable crops.
In English usage 'beans' sometimes also refer to seeds or other organs of non leguminosae which bear a resemblance to the vegetable, for example coffee beans, castor beans and cocoa beans (which resemble bean seeds), and vanilla beans (which resemble the pods)
Beans are one of the longest-cultivated plants, broad beans having been grown at least since ancient Egypt, the common bean for six thousand years in the Americas.
Many modern dry beans come from old-world varieties of broad beans, but most of the kinds commonly eaten fresh come from the Americas, being first seen by Christopher Columbus during his conquest of a region of what may have been the Bahamas, where they were grown in fields.
One especially famous use of beans by pre-Columbian people is the Three Sisters method of companion plant cultivation: On the east coast of what would come to be called the United States, some tribes would grow corn (maize), beans, and squash intermingled together, a system which had originated in Mexico. The corn would not be planted in rows as it is today, but in a checkerboard/hex fashion across a field, separate patches of one to four stalks each. Beans would be planted around the base of the developing stalks, and would vine their way up as the stalks grew. All American beans at that time were vine plants, "bush beans" having only been bred more recently. The cornstalks would work as a trellis for the beans, and the beans would provide much-needed nitrogen for the corn. Squash would then be planted in the spaces between the patches of corn in the field. They would be provided slight shelter from the sun by the corn, and would deter many animals from attacking the corn and beans, because their coarse, hairy vines and broad, stiff leaves are difficult or uncomfortable for animals like deer and racooons to walk through, crows to land on, et cetera.
Beans were an important alternative source of protein throughout old and new world history, and still are today. There are over 4,000 cultivars of bean on record in the United States, alone. However beans, like most plants, do not have a complete set of amino acids, and are therefore dangerous to depend upon as a sole source of protein.
An interesting modern example of the diversity of bean use is 15 bean soup, which, as the name implies, contains literally fifteen different varieties of bean.
 Types of beans
 Cultural aspects
The following traditional uses of beans refer to the broad bean.
Some kinds of raw beans and especially red kidney beans, contain harmful toxins (lectins) which need to be removed, usually by soaking and cooking. The soaking water from kidney beans should be discarded before boiling.
Soak in water for at least 5 hours. Pour away the water. Boil briskly in fresh water, with occasional stirring, for at least 10 minutes. Undercooked beans may be more toxic than raw beans.
Cooking beans in a slow cooker, because of the lower temperatures often used, may not destroy toxins even though the beans do not smell or taste 'bad' (though this should not be a problem if the food reaches boiling and stays there for some time).
Many edible beans, including broad beans and soybeans, contain oligosaccharides (particularly Raffinose and Stachyose), a type of sugar molecule also found in cabbage. An anti-oligosaccharide enzyme is necessary to properly digest these sugar molecules. As a normal human digestive tract does not contain any anti-oligosaccharide enzymes, consumed oligosaccharides are typically digested by bacteria in the large intestine. This digestion process produces flatulence-causing gases as a byproduct. This aspect of bean digestion is the basis for the children's rhyme "Beans, Beans, the Musical Fruit."
Some species of mold produce alpha-galactosidase, an anti-oligosaccharide enzyme, which humans can take to facilitate digestion of oligosaccharides in the small intestine. This enzyme, currently sold in the U.S. under the brand-name Beano, can be added to food or consumed separately.
Other strategies include soaking beans in water for several hours before mixing them with other ingredients to remove the offending sugars. Sometimes vinegar is added, but only after the beans are cooked as vinegar interferes with the beans' softening.
Fermented beans will not produce most of the intestinal problems that unfermented beans will, since bacteria can consume the offending sugars.