What is the main difference between refrigerator and deep freezer?

A refrigerator (often called a "fridge" for short) is a cooling appliance for the storage and preservation of perishable food; food kept in a refrigerator lasts longer than that left at room temperature as the cold inhibits bacterial growth. A refrigerator maintains a cold temperature above the freezing point of water. The refrigerator is a relatively modern invention amongst kitchen appliances. It replaced the common icebox which had been a household item for almost a century and a half prior, and is sometimes still called by the original name "icebox". The word freezer is generally used to describe an appliance that keeps foods frozen. Freezers are common as household units for storing food but are also used in commercial settings. Most freezers operate around -18 °C (0 °F). Domestic freezers can be included as a compartment in a refrigerator or can be standalone units. Domestic freezers are generally upright units, resembling refrigerators, or chests, resembling upright units laid on their backs. Many modern freezers come with an icemaker. Commercial fridge and freezer units, which go by many other names, were in use for almost 40 years prior to the common home models. The fact that they operated with toxic ammonia gas systems made them unsafe for home use. Practical household refrigerators were introduced in the 1920s and gained wider acceptance in the 1930s as prices fell and non-toxic, nonflammable synthetic refrigerants, such as Freon or R-12 refrigerants were introdu