Jack-o-lantern is the real name for the carved pumpkin.
Its glowing face was supposed to scare away evil spirits.
You carried it around the edge of your village or let it burn outside your house on Hallowe'en night.
In Ireland Jack-o-lanterns were carved out of turnips. Lots of Irish people went to live in America.
They still wanted to make lanterns but they couldn't find enough turnips. They used pumpkins instead.