The onion (Allium cepa L.), also referred to as the bulb onion or common onion, is a vegetable. This particular species is the most extensively produced species of the genus of Allium. The onion plant is usually a biennial or perennial plant. When cultivated however, the plant is mostly handled as an annual and harvested at the end of its first production season.
Onions are popular and therefore cultivated and used for cooking all around the world. Their flesh is pungent when chopped, because it contains particular chemical elements that irritate the eyes.