A walk-in freezer is a large, insulated room that is used to store food and other items at very low temperatures. It is also known as a REEFER, which is a six-letter word commonly used in crosswords. The purpose of a walk-in freezer is to keep food and other items fresh for longer periods of time, while also protecting them from spoilage due to temperature fluctuations. Walk-in freezers are typically found in restaurants, grocery stores, and other commercial establishments.