Top hat

A top hat was a type of hat.

The Eleventh Doctor owned a top hat, which he wore at Amy and Rory's wedding, (TV: The Big Bang) after having been poisoned by River Song in Nazi Germany (TV: Let's Kill Hitler) and again to conceal a device that allowed him to lure the Squall back into their dimension of origin. (PROSE: Paradox Lost)

During his retirement to the Victorian era, the Doctor wore a battered felt top hat, a burgundy frock coat, a waistcoat with collars and a pocket watch with a fob chain. (TV: The Great Detective, The Snowmen)