A cozy retreat is a place of relaxation and comfort, often found in nature. It can be a DEN, an INN, or a NEST. A DEN is a small, enclosed space, usually in a cave or underground, that provides shelter and protection. An INN is a commercial establishment providing lodging, meals, and other services for travelers. A NEST is a structure built by birds or other animals to hold their eggs and young. All three of these terms can be used to describe a cozy retreat.