Lanyard

A lanyard is a cord or strap worn around the neck, shoulder, or wrist to carry such items as keys or identification cards. In the military, lanyards were used to fire an artillery piece or arm the fuze mechanism on an air-dropped bomb by pulling out a cotter pin (thereby starting the arming delay) when it leaves the aircraft. Aboard a ship, it may refer to a piece of rigging used to secure or lower objects.

The earliest references to lanyards date from 15th century France: "lanière" was a thong or strap apparatus. In the French military, lanyards were used to connect a pistol, sword or whistle (for signalling) to a uniform semi-permanently. Lanyards were used by cavalry and naval officers at sea. A pistol lanyard can be easily removed and reattached by the user, but will stay connected to the pistol whether it is drawn or in a holster. In the 1966 Spaghetti Western The Good, The Bad, and The Ugly, two of the main characters, Tuco Ramirez & William Weinberg, carries his pistol on a rope cord lanyard. Eli Wallach, the actor who played the part of Tuco, reportedly told director Sergio Leone that it was too difficult to put a pistol into a holster without looking, so Leone put Wallach's pistol on a lanyard.

In the military, lanyards of various colour combinations and braid patterns are worn on the shoulders of uniforms to denote the wearer's qualification or regimental affiliation. In horse regiments, lanyards were worn on the left, enabling a rider to pull a whistle from the left tunic pocket and maintain communication with his troop. Members of the British Royal Artillery wear a lanyard which originally held a key for adjusting the fuzes of explosive shells.

...
Wikipedia