Question mark

The Seventh Doctor wearing a jumper covered in question marks, and holding his umbrella, with a handle shaped like a question mark. (GRAPHIC: Doctor Who Evergreen)

The question mark, ?, was a punctuation mark used in many documents on Earth to denote an interrogative. In emoji, ❓ was the symbol for confusion. (TV: Smile)

As fashion for the Doctor

Some incarnations of the Doctor had question marks on their outfits. The Fourth, Fifth and Sixth Doctors displayed question marks on the collars of their shirts. (TV: Castrovalva, The Twin Dilemma) In an encounter with the Fifth Doctor, the Tenth Doctor gleefully noted his former self's question marks. (TV: Time Crash)

The Seventh Doctor wearing a jumper covered in question marks. (TV: Battlefield)

The Seventh Doctor wore a jumper covered with the symbol (TV: Time and the Rani) and carried an umbrella with a large red question mark-shaped handle (TV: Delta and the Bannermen) and a business card with a stylised question mark. (TV: Remembrance of the Daleks) When asked to sign his name, he did so with a question mark. (TV: The Invasion of Time)

The Fifth and Seventh Doctors also had a pair of question mark pyjamas. (PROSE: Divided Loyalties, Question Mark Pyjamas, AUDIO: The Magic Mousetrap)

When Osgood asked the Twelfth Doctor why he stopped wearing question marks, he told her that he now wore question mark underpants. (TV: The Zygon Invasion)

Several alternate versions of the Eighth Doctor wore question mark clothing. The Eighth Doctor that married Grace Holloway wore question mark underpants. Joe Smith, a version of the Doctor who worked as a private investigator, wore a question mark tie. (COMIC: The Glorious Dead)