Chin

A chin was part of the Human anatomy sometimes other species had this feature e.g, Time Lords.

The Eleventh Doctor was remarked often for having a slightly large one, whivh got himself nicknamed (irono ally by his previous self) "Chinny". (TV: The Day of the Doctor)

Behind the Scenes
The Tenth Doctor referred to him as "Chin" in the NOTVALID Doctor Who Cinema Introduction.