Home › Words › H › hoatzinhoatzin/ˈwætsɪn/hoatzin · noun — A bird of the species Opisthocomus hoazin of the order Opisthocomiformes, with claws on the wing fingers of the juvenile and an enlarged crop used as a rumen.Definition from Wiktionary (CC BY-SA 3.0).hoatzin is pronounced /ˈwætsɪn/.EtymologyFrom Nahuatl huāctzin (which probably designated a different bird).nounA bird of the species Opisthocomus hoazin of the order Opisthocomiformes, with claws on the wing fingers of the juvenile and an enlarged crop used as a rumen.Definitions & examples from Wiktionary (CC BY-SA 3.0).