The term 'potato bag' can be summarized as a SACK, which is a four-letter word. A SACK is a type of bag that is typically made from a strong material such as burlap or canvas and is used to store and transport items such as potatoes. It is usually large and open at the top, allowing for easy access to the contents. The SACK is also commonly used to store other items such as grain, flour, and other agricultural products.