A hidden compartment or secret compartment is a compartment whose existence or access is not obvious at first glance, and can be used as a hiding place for objects or sometimes even for people.
A hidden compartment where people can stay is usually referred to as a hidden room or secret room, and can range from parts of small wardrobes or closets under staircases to entire basements or even large mountain complexes. Hidden rooms are often accessed via a hidden door, which for example can be camouflaged as a bookshelf or a trapdoor in the floor. Hidden rooms can for example be used as a refuge, media room, larder or wine cellar.
The term hidden compartment can also refer to smaller storage places for valuables and personal belongings in furniture (such as cabinet compartments), trap compartments in vehicles, false bottoms in containers, and various other concealment devices.