jeans

The word comes from Gene(s) or Jean(s), an old English name for the Italian city of Genoa. It first described a coarse cotton cloth associated with that city, called Gene(s) fustian, before being applied to trousers made from it.

In the 19th century, the cloth's name shifted to name the trousers themselves, and the final -s was reanalyzed as a plural ending, as though the garment were inherently made of two parts rather than a single fabric.

The French name for Genoa, Gênes, mirrors the same city origin, showing how this place name traveled into everyday cloth vocabulary.