A jack-o'-lantern (or jack o'lantern) is a carved pumpkin or turnip lantern, associated with the holiday of Halloween and named after the phenomenon of a strange light flickering over peat bogs, called will-o'-the-wisp or jack-o'-lantern. In a jack-o'-lantern, the top of the pumpkin or turnip is cut off to form a lid, the inside flesh is scooped out, and an image — usually a monstrous or comical face – is carved out of the rind to expose the hollow interior. To create the lantern effect, a light source is placed within before the lid is closed. The light source is traditionally a flame such as a candle or tea light, but artificial jack-'o-lanterns with electric lights are also marketed. It is common to see jack-o'-lanterns on doorsteps and otherwise used as decorations prior to and on Halloween.
The term jack-o'-lantern was originally used to describe the visual phenomenon ignis fatuus (lit., "foolish fire") known as a will-o'-the-wisp in English folklore. Used especially in East England, its earliest known use dates to the 1660s. The term "will-o'-the-wisp" uses "wisp" (a bundle of sticks or paper sometimes used as a torch) and the proper name "Will": thus, "Will-of-the-torch." The term jack-o'-lantern is of the same construction: "Jack of [the] lantern."
The carving of vegetables has been a common practice in many parts of the world, and gourds were one of the earliest plant species domesticated by humans c. 10,000 years ago. For example, gourds were used to carve lanterns by the Maori over 700 years ago; the Māori word for a gourd also describes a lampshade.
It is believed that the custom of making jack-o'-lanterns at Halloween began in Ireland. In the 19th century, "turnips or mangel wurzels, hollowed out to act as lanterns and often carved with grotesque faces," were used at Halloween in parts of Ireland and the Scottish Highlands. In these Celtic-speaking regions, Halloween was also the festival of Samhain and was seen as a time when supernatural beings (the Aos Sí), and the souls of the dead, roamed the earth. The belief that the souls of the dead roamed the earth at Halloween was also found in other parts of Europe. Jack-o'-lanterns were also made at Halloween in Somerset (see Punkie Night) during the 19th century.