door /dɔːr/ aep /dɔːr/ noun [C]
A1 a flat object that is used to close the entrance of something such as a room or building, or the entrance itself:
» the front door» the back door» a car door» a sliding door» The door to his bedroom was locked.» We could hear someone knocking at/on the door.» Could you open/close/shut the door, please?» She asked me to answer the door (= go and open it for someone).See picture: door 
Thesaurus+: ↑Doors and parts of doorsbe on the door
F0 to work at the entrance of a building, collecting tickets or preventing particular people from entering
Thesaurus+: ↑Defending and protecting , ↑Backing, supporting and defending , ↑Preserving and savingF0 used to refer to a house or other building:
» Sam only lives a few doors (away/up/down) from us.» The people next door (to us) (= living in the house next to us) aren't very friendly.Thesaurus+: ↑Houses and homesout of doorsF0 outside in the open air
Thesaurus+: ↑From, out and outside• • •
Extra Examples:» I'd only gone a little way down the street when I remembered I hadn't locked the door.» The sign on the toilet door said 'Engaged'.» Our new sofa doesn't fit through the door.» Soldiers guard the main doors of the embassy.» He got his bag caught in the train doors as they were closing.