Onion is a widely used vegetable known for its pungent aroma, sharp flavor, and versatility in cooking. It belongs to the allium family, which also includes garlic, leeks, and shallots. Onions are used in cuisines across the world, either raw in salads and sandwiches or cooked in a variety of dishes to enhance flavor. They are rich in antioxidants, especially quercetin, and contain vitamins and minerals that contribute to overall health, including support for heart health and immune function. Depending on the type—red, white, or yellow—onions can add sweetness, spice, or depth to recipes, making them a staple ingredient in countless culinary traditions.