In the Mongol Empire, the title of khan was used for the Great Khan, who was the supreme ruler of the empire, as well as for the rulers of subordinate khanates. The title of khan was also used by the rulers of the various khanates that emerged after the collapse of the Mongol Empire, such as the Kazakh Khanate, the Uzbek Khanate, and the Khanate of Kazan.
In modern times, the title of khan is still used by the rulers of some Muslim countries, such as Pakistan and Afghanistan. It is also used as a surname in many parts of Asia.
The name khan can also be used to refer to a ruler who is not a Muslim. For example, in the early Middle Ages, the khans of the Golden Horde were not Muslim. In modern times, the khans of Mongolia are not Muslim.
The name khan is sometimes used in a derogatory way to refer to a person who is considered to be a tyrant or a dictator.