Young Blonde Girl In The Room With A Chair Posing At The Door

Hinged doors
Most doors are hinged along one side to allow the door to pivot away from the doorway in one direction but not in the other. The axis of rotation is usually vertical. In some cases, such as hinged garage doors, the axis may be horizontal, above the door opening.
Doors can be hinged so that the axis of rotation is not in the plane of the door to reduce the space required on the side to which the door opens. This requires a mechanism so that the axis of rotation is on the side other than that in which the door opens. This is sometimes the case in trains, such as for the door to the toilet, which opens inward.
A swing door has special hinges that allow it to open either outwards or inwards, and is usually sprung to keep it closed.