Box

Following a stopover in 1963 London, the Doctor's TARDIS was stuck with the exterior shape of a telephone box, specifically a police box, due to a malfunction in its chameleon circuit. (TV: "The Cave of Skulls") As the First Doctor explained to Ian Chesterton and Barbara Wright, the box was an entrance chamber to a fourth dimension, leading directly into the control room. (COMIC: The Secrets of the Tardis)

The Doctor would continue to refer to his TARDIS as a "box" all throughout their lives; the Eleventh Doctor called himself "a madman with a box" (TV: The Eleventh Hour) and, while believing he was dying, looked back on his story as that of "a daft old man who stole a magic box and ran away". (TV: The Big Bang) His next regeneration, at a turning point in understanding himself, proclaimed himself "an idiot! With a box, and a screwdriver!". (TV: Death in Heaven)

Pandora's box was a legendary item to which the Pandorica bore a resemblance. Before he was made aware of its true nature by the Dalek members of the Alliance, the Eleventh Doctor also derisively called the Pandorica "a box". (TV: The Pandorica Opens)

An advanced, interactive computer who served as Liz Shaw's companion shortly before her retirement from the Preternatural Research Bureau also went by the name of Box, as, indeed, she resembled one. (HOMEVID: When to Die)