flat, movable structure used to open and close an entrance

A door is a hard, flat object a person can open and close so that person can go into a room or other place. It is found in houses and other buildings. Doors are also found in cars and cages.


The reasons for a door are:

  • for people, animals, and objects to go through; some doors are for emergencies only (emergency exit)
  • to keep cold or hot air outside (or inside, such as the door on a refrigerator)
  • so that people cannot see or hear what happens on the other side (privacy and stopping noise)
  • so that people do not fall out of the car or other vehicle
  • so a person can decide who to let in—many doors have a lock

Types of doors


A revolving door is a group of doors that turn in a circle as a person pushes one. The person can go through, but wind and rain cannot get in.

A blind door is a fake door that is really part of the wall. People use them to make a room look nice.

An up-and-over door is often used in garages. Instead of hinges, it rolls up on rails so that it stays above the opening.

A fire door is a door that does not let fire go through. They are usually made of heavy steel.

A doggie door is a small door for dogs or other small pets. They are usually on the bottom of people-sized doors.