duster coat

A loose-fitting, lightweight long coat, originally worn by horsemen to protect their clothes from dust (hence the name). The duster later evolved into the drover coat, a variant usually made from oilcloth or waxed fabric and sporting a capelet. Commonly associated with cowboy fashion and the American Old West in popular culture, largely from its frequent use as a wardrobe item in Western films.

This tag implicates coat (learn more).