A hair net is a piece of cloth used to cover the hair while cooking. In the kitchen, loose hair can be a hazard when it falls into food.
Hair nets are especially important in commercial kitchens, where food safety regulations often require them. In addition to keeping hair out of food, they can also protect hair from heat and grease. Historically, hair nets were made of cotton or linen, but modern hair nets are often made of disposable materials such as nylon or plastic.