A door is a moving structure used to block off, and allow access to, an entrance to or within an enclosed space, such as a building or vehicle. Similar exterior structures are called gates. Typically, doors have an interior side that faces the inside of a space and an exterior side that faces the outside of that space. While in some cases the interior side of a door may match its exterior side, in other cases there are sharp contrasts between the two sides, such as in the case of the vehicle door. Doors normally consist of a panel that swings on hinges or that slides or spins inside of a space.

Simon Godfried Albert Doorenbos (7 October 1891, Barneveld – 1980) was a Dutch horticulturist best known for his work as Director of The Hague Parks Department from 1927 until his retirement in 1957, with a brief interruption during the Second World War when he was dismissed and evicted by the Nazis for refusing to remove trees and shrubs to facilitate the construction of a V1 flying bomb launch pad.