Read the dictionary definition of door. All definitions for this word.
1. a swinging or sliding barrier that will close the entrance to a room or building or vehicle
1. he knocked on the door
2. he slammed the door as he left
2. a room that is entered via a door
1. his office is the third door down the hall on the left
3. a structure where people live or work (usually ordered along a street or road)
1. the office next door
2. they live two doors up the street from us
4. the entrance (the space in a wall) through which you enter or leave a room or building; the space that a door can close
1. he stuck his head in the doorway
5. anything providing a means of access (or escape)
1. we closed the door to Haitian immigrants
2. education is the door to success