jack-o'-lanternEnglishOxford New American Dictionaryjack-o'-lantern /ˈjakəˌlan(t)ərn, ˈdʒækəˌlæn(t)ərn / ▸ noun 1 a lantern made from a hollowed-out pumpkin in which holes are cut to represent facial features, typically made at Halloween. 2 archaic an ignis fatuus.