The term uniform was used to refer to the clothing worn for the purpose of displaying membership in an organisation. During the Trojan War, Steven Taylor noted that, by taking a uniform, he would be captured as a prisoner of war instead of a spy. (TV: The Myth Makers)
Bus drivers wore uniforms. In the early 21st century, the Ninth Doctor wore one while hijacking the 68 to Bolton. (PROSE: Have You Seen This Man?)
Police officers wore uniforms. By 2018, English police uniforms included uniform cameras. (TV: The Tsuranga Conundrum)
At school, school uniforms were worn by students. (TV: The Curse of Clyde Langer)
Gwen Cooper reported to her fellow Cardiff police officer Andy Davidson of a man in a porter's uniform being attacked by a man wearing a mask. (TV: Everything Changes)
The Moroks were distinguished from the Xerons by their uniforms. (TV: The Space Museum)
The US naval uniform was worn by members of the United States Navy. (TV: Praxeus)
During the 2000s, red caps constituted part of the uniform of UNIT soldiers. (TV: The Sontaran Stratagem/The Poison Sky) Reuniting with his old friend Martha Jones, now a member of UNIT, Jack Harkness jokingly asked if she could provide him with a red cap, suggesting that Ianto Jones would look good in one. Martha told Jack to get his own uniform. (TV: Reset)
While working for Torchwood Three, (TV: Children of Earth: Day Four et al.) Captain Jack Harkness wore what Owen Harper described as a "military uniform." (TV: Fragments) His attire would earn him the nickname "World War II" from Rex Matheson. (TV: Rendition et al.) He did not always wear it in full though, something Bilis Manger noted when encountering Jack in 1940s war-time Britain. Jack, having came there by accident, lied that he was on leave for 48 hours. (TV: Captain Jack Harkness)
In 2323, Lieutenant Georgette Gold wore an intelligent uniform which could "[neutralise]" itself, removing her military insignia from view in public areas so as to avoid causing alarm. (COMIC: Liberation of the Daleks [+]Alan Barnes, DWM Comics (Panini Comics, 2022).)
In a parallel universe, uniforms were worn by individuals serving in the Starfleet of the United Federation of Planets. (COMIC: Assimilation)