Onion

Onion (Allium cepa), herbaceous biennial plant and its edible bulb. The onion is probably native to southwestern Asia but is now grown throughout the world, chiefly in the temperate zones. The plant belongs to the lily family, Alliaceae; however, some classifications place it in the family Liliaceae. Most members of both families have an underground storage system, such as a bulb or tuber. Other members of this family include ornamental plants such as the tulip, hyacinth, and lily-of-the-valley and edible plants such as the leek, garlic, and chive.