Meaning of “door” - Learner’s Dictionary

door

noun [ C ] uk us /dɔːr/
THING YOU OPEN

A1 the part of a building, room, vehicle, or piece of furniture that you open or close to get inside it or out of it:

Please shut the door behind you.
I can't open the door.
There's someone at the door.
SPACE

the space in a wall where you enter a building or room:

He led us through the door to the rear of the building.
behind closed doors

privately and not in public:

Most of the deals were done behind closed doors.
two/three, etc doors away

in a place that is two/three, etc houses away:

We live just a few doors away from the Smiths.
→ See also trap door

(Definition of “door” from the Cambridge Learner’s Dictionary © Cambridge University Press)