Onion (प्याज), scientifically known as Allium cepa, is a widely used vegetable known for its pungent flavor and aroma. It is rich in vitamin C, antioxidants, and sulfur compounds with culinary and medicinal benefits. Onions are versatile, used raw, cooked, or pickled, and come in varieties like red, white, and green onions. They are a staple ingredient in global cuisines.