1. a hinged, sliding, or revolving barrier at the entrance to a building, room, or vehicle, or in the framework of a cupboard: "she looked for her key and opened the door"
▪ a doorway: "she walked through the door"
▪ used to refer to the distance from one building in a row to another:"they lived within three doors of each other"
Word OriginOld Englishduru, dor, of Germanic origin; related to Dutch deur ‘door’ and German Tür ‘door’, Tor ‘gate’; from an Indo-European root shared by Latin foris ‘gate’ and Greek thura ‘door’.