ponchoPronunciation: /ˈpɒn(t)ʃəʊ/Definition of poncho noun (plural ponchos) a garment of a type originally worn in South America, made of a thick piece of woollen cloth with a slit in the middle for the head. a waterproof garment in the style of a poncho worn as a raincoat. Origin: early 18th century: from South American Spanish, from Araucanianponcho in other Oxford dictionaries Definition of poncho in the US English dictionary