Onions are a vegetable with a strong smell and taste that are often used in cooking. Here are some characteristics of onions: (1) Appearance Onions are biennial plants that are usually grown as annuals. They have fleshy, hollow, cylindrical leaves that are yellowish- to bluish green in color. The leaves grow in a flattened, fan-shaped swathe, with the base of each leaf being a white sheath that grows out of the bulb. (2) Flavor Onions are pungent and have a distinct flavor due to the sulfur compounds they contain. (3) Uses Onions are used in many cuisines and are an essential ingredient in many African sauces and relishes. They are also served as a cooked vegetable and add flavor to dishes like stews, roasts, soups, and salads. (4) Nutrition Onions are low in nutrients but are a good source of vitamin C. A medium raw onion contains 60 calories, 1 gram of protein, 14 grams of carbohydrates, 0 fat, 0 cholesterol, 10 mg of sodium, 200 mg of potassium, and 11.9 mg of vitamin C. (5) History Onions are likely native to southwestern Asia but are now grown worldwide. They have been consumed widely for thousands of years and are one of the hardiest and oldest garden vegetable plants.