Also known as bulb onions or common onions, they are vegetables and the most widely cultivated species of the genus Allium. They are also known as Pyazor Kanda or Dungri (Hindi), Nirulli/Ullipayalu/Yerra Gaddalu (Telugu), Vaengayam(Tamil), Savala (Malayalam), Ulligadde/Erulli/Neeruli (Kannada), Pyajj/Piyaz(Bengali), Dungri/Kanda (Gujarati), and Kandaa (Marathi). Other related vegetables include garlic, leeks, chives, shallots, and Chinese onions. The onion plant has bluish-green leaves, and the bulb at the base begins to swell after a certain period.
Onions are cultivated and consumed across the world. They are usually served cooked. They can also be eaten raw and are used in pickles and chutneys. The onion has a strong taste and a sharp, pungent flavor. Though it is a temperate crop, it can be grown under a wide range of climatic conditions (temperate, tropical, and subtropical).