President

President was the title given to the heads of state, usually of a republic, or the figure who presided over a governmental or corporate body.

On Earth, the United States of America was governed by a president. In Pete's World, Great Britain also had a president. (DW: Rise of the Cybermen) Later, the whole of Earth had a president. (DW: Frontier in Space)

There were also presidents on other worlds, such as the Lord President of Gallifrey, the President of Androzani Major, (DW: The Caves of Androzani) the President of Fangoria. (PDA: Warmonger)