A door is a piece of wood, glass, or metal, which is moved to open and close the entrance to a building, room, cupboard, or vehicle.

A door is the space in a wall when a door is open.

The door is the entrance to a large building such as a shop, hotel, or theatre.

Doors is used in expressions such as a few doors down or three doors up to refer to a place that is a particular number of buildings away from where you are.

When you answer the door, you go and open the door because a visitor has knocked on it or rung the bell.

If you say that someone gets or does something by the back door or through the back door, you are criticizing them for doing it secretly and unofficially.

If someone closes the door on something, they stop thinking about it or dealing with it.

If people have talks and discussions behind closed doors, they have them in private because they want them to be kept secret.

If someone goes from door to door or goes door to door, they go along a street calling at each house in turn, for example selling something.

If you talk about a distance or journey from door to door or door to door, you are talking about the distance from the place where the journey starts to the place where it finishes.

If you say that something helps someone to get their foot in the door or their toe in the door, you mean that it gives them an opportunity to start doing something new, usually in an area that is difficult to succeed in.

If someone shuts the door in your face or slams the door in your face, they refuse to talk to you or give you any information.

If you lay something at someone'sdoor, you blame them for an unpleasant event or situation.

If someone or something opens the door to a good new idea or situation, they introduce it or make it possible.

When you are out of doors, you are not inside a building, but in the open air.

If you see someone to the door, you go to the door with a visitor when they leave.

If someone shows you the door, they ask you to leave because they are angry with you.