Jack o’ lantern

Jack o’Lantern is another name for will o’ the wisp from about the mid-17th century but, from the mid-19th century, it also became the name for the carved out pumpkin faces into which candles were put at Halloween in America. It is believed Irish immigrants brought the practice with them from Ireland where large potatoes or turnips were traditionally used for the same purpose. The superstition was that such practices would ward off evil spirits at Halloween. See also will o’ the wisp.