Beret

A beret was a type of hat.

UNIT soldiers and officers alike wore berets in the field. Over the years, the standard-issue UNIT field beret changed from chocolate brown (TV: The Ambassadors of Death) to khaki green (TV: Terror of the Autons) to United Nations blue (TV: Battlefield) to red. (TV: Aliens of London, Planet of the Dead) In Donna's World, UNIT berets were black. (TV: Turn Left)