pantaloon

Borrowed from French pantalon, itself from Italian Pantalone, a stock character in Commedia dell'arte, whose name came from the Spanish surname Pantaleon.

The word moved from being a specific character's name to describing the loose trousers he wore onstage, and eventually became a general term for trousers themselves.

It shares its root with French pantalon, still the everyday French word for trousers.