Onion is a term used for many plants in the genus Allium. They are known by the common name "onion" but, used without qualifiers, it usually refers to Allium cepa. Allium cepa is also known as the "garden onion" or "bulb" onion. It is grown underground by the plant as a vertical shoot that is used for food storage, leading to the possibility of confusion with a tuber, which it is not.
Allium Cepa is known only in cultivation, but related wild species occur in Central Asia. The most closely-related species include Allium vavilovii Popov & Vved. and Allium asarense R.M. Fritsch & Matin from Iran. However Zohary and Hopf warn that "there are doubts whether the vavilovii collections tested represent genuine wild material or only feral derivatives of the crop."
Onions, one of the oldest vegetables known to humankind, are found in a large number of recipes and preparations spanning almost the totality of the world's cultures. They are nowadays available in fresh, frozen, canned, pickled, powdered, chopped, and dehydrated forms. Onions can be used, usually chopped or sliced, in almost every type of food including cooked foods and fresh salads and as a spicy garnish. They are rarely eaten on their own but usually act as accompaniment to the main course. Depending on the variety, an onion can be sharp, spicy, tangy and pungent or mild and sweet.
Onions pickled in vinegar are eaten as a snack. These are often served as a side serving ...