door in WordNet English dictionary

1. 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"
   door 
   
2. the entrance (the space in a wall) through which you enter or leave a room or building; the space that a door can close
   "he stuck his head in the doorway"
   doorway  door  room access  threshold 
   
3. a room that is entered via a door
   "his office is the third door down the hall on the left"
   door 
   
4. 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"
   door 
   
5. anything providing a means of access (or escape)
   "we closed the door to Haitian immigrants"; "education is the door to success"
   door