A deep fryer, or deep fat fryer, is a kitchen appliance used for deep frying. They're an appliance which can hold and heat Cooking Oil in which to put food into for cooking. Most deep fryers feature a metal basket in which to lower food into the fryer and retrieve it when done cooking.
Deep Frying is a method of cooking in which food is fully submerged into oil at high heat. Dedicated deep fryers are generally preferred over deep frying using a pot and stove, as deep fryers are better able to regulate oil temperatures.