A Cyberman is fused with the door to the bridge. (TV: Earthshock)

A door was an architectural feature blocking or allowing access to another space.

Hafsa helped Maimuna hide Barbara Wright from El Akir by keeping watch at the door. (TV: The Crusade)

The Doctor's TARDIS, as used by the First Doctor, had two doors, the outer door of the exterior entrance chamber, followed by the inner door which led to a fourth dimension, beginning with the control room. (COMIC: The Secrets of the Tardis)

After the Second Doctor disappeared from the TARDIS, Jamie and Zoe were startled to hear knocking on the TARDIS door, as they were travelling in the Vortex. (PROSE: Undercurrents)

The War Doctor, scanning the prison door in the Tower of London. (TV: The Day of the Doctor)

Trying to kill the Third Doctor, the Master attached a volataliser to a door at the Deep Space Research Centre No. 2, so that if anyone tried to open the door it would fall to the ground and destroy the building. The Doctor was able to act quickly enough to catch it before it detonated. (PROSE: Doctor Who and the Terror of the Autons)

The access code to open the door from the Chancellor's office to the President's office on Gallifrey was the spoken phrase "there's nothing more useless than a lock was a voice print", a popular saying of Borusa's, were spoken. (TV: The Invasion of Time)

The Fifth Doctor tapped into the antimatter storage system on Briggs' freighter and used it to stabilise the door just as a Cyberman breaks through, fusing it into the door. (TV: Earthshock)

The Twelfth Doctor looking through the door of the shrunken TARDIS. (TV: Flatline)

When an intelligent Earth species reached the edge of the Solar System, they and their entire timeline were sucked through a door into Time's End. This happened to billions of species until it was stopped by the Sixth Doctor. (AUDIO: The Nowhere Place)

The Watcher was on duty at the door of a Vrill colony. The Seventh Doctor referred to him as a "butler-fly". (AUDIO: Survival of the Fittest)

A Tele-door was a teleport system that allowed an individual to travel vast spaces by merely walking through a door. (PROSE: The Tomorrow Windows)

When the War Doctor, Tenth Doctor and Eleventh Doctor were imprisoned in the Tower of London in the 16th century, none of them checked to see if the door was locked. (TV: The Day of the Doctor)

The Twelfth Doctor was trapped in the TARDIS when it shrank so much from the Boneless' influence that he could not fit through the door. (TV: Flatline) This same incarnation of the Doctor later remarked that it was impossible to form a bond with a door, as they were "notoriously cross" with their lives, such as they were, consisting of people "pushing past them". (TV: Heaven Sent)