A door is a panel that is usually made of a tough, impermeable, and difficult-to-break material (like wood or metal), with or without windows, but sometimes consisting of a hard frame into which glass or screens have been fitted, attached to hinges by which it is attached to a frame that constitutes a space for ingress into or egress from a building, room, or vehicle, such that the panel may be moved in various ways (at angles away from the frame, by sliding In most instances, the form of a door’s interior is identical to that of its exterior, but in some instances (for example, a car door), the form of the door’s interior and exterior are radically dissimilar to accommodate behaviours of entering and exiting that are distinct from one another. Doors typically have locking mechanisms to ensure that only the owner, custodian, or other individuals who have rightful access to a space can open them. Additionally, doors may have knockers or doorbells that enable individuals on the outside to announce their presence and summon someone to either open the door for them or give permission for them to open and enter. A door’s primary purpose is to allow passage into and out of a room; however, in addition to this primary function, doors can also serve the secondary purposes of separating areas that have distinct functions, allowing light to enter and exit a room, controlling ventilation or air draughts so that interiors can be heated or cooled more efficiently, reducing noise, and preventing the spread of fire. All of these functions are in addition to the primary purpose of providing access into and out of a room. Doors can serve a variety of purposes, including those related to appearance, symbolism, and ritual. The act of moving from the position of an outsider to that of an insider might be symbolised by being given the key to a door. Doors and doors are symbols that are commonly used in literature and the arts to represent transition or change in a metaphorical or allegorical capacity.