Dehydrated onion is a food product made from onions that have been dried and then ground into pieces. The onions are dried through a variety of methods, such as air-drying, oven-drying, or a combination of both. The drying process removes the majority of the moisture from the onions, which results in a product that has a longer shelf life and is easier to store. Dehydrated onions are widely used in many recipes, including soups, stews, casseroles, and more, as they provide a flavor that is similar to fresh onions.