Definition of door

• a swinging or sliding barrier that will close the entrance to a room or building or vehicle; "he knocked on the door"; "he slammed the door as he left"
• anything providing a means of access (or escape); "we closed the door to Haitian immigrants"; "education is the door to success"
• a structure where people live or work (usually ordered along a street or road); "the office next door"; "they live two doors up the street from us"