Technically, a 'Jack O Lantern' is a term used to describe a carved pumpkin that has some kind of a light in it. Usually, the carved pieces will be facial features (eyes, nose, mouth..). Jack O Lanterns are most often seen during the fall or Halloween season. This is because that time of the year coincides with the harvesting of pumpkins. Really, these lanterns can be made out of anything from plastic ro vegetables.