Kes and Chakotay wearing armbands
An armband was a device or a piece of material which was worn around the arm, over the sleeve of other clothing if present. Members of the Nazi Party, the Cult of the Pah-wraiths, and the Romulan Rebirth movement all wore armbands as part of their uniforms, to show the allegiance of the wearers. (In the case of the Romulan Rebirth movement, their armbands were the only consistent aspect of their attire) (TOS: "Patterns of Force"; DS9: "Image in the Sand ", "Covenant"; PIC: "Absolute Candor")
Nyota Uhura once wore a black fabric armband at her communications station on the bridge of the USS Enterprise in 2267. (TOS: "The City on the Edge of Forever") Technological armbands creating an antipolaric field were worn by a landing party from the USS Voyager, while surveying Makull's homeworld in 2371. (VOY: "Time and Again")
These 24th century armbands are not named on screen; their designation as "armbands" comes from the script of "Time and Again".