A jack-o'-lantern is a carved pumpkin that is often used as a decoration during the Halloween season. People typically cut off the top of the pumpkin, scoop out the insides, and then carve a face or design into the outer shell. Once finished, a candle or light is placed inside, making the pumpkin glow and creating a spooky or fun atmosphere. The tradition of making jack-o'-lanterns originated from an old Irish custom. Originally, people carved turnips or potatoes, but when Irish immigrants came to America, they discovered that pumpkins were larger and easier to carve. Today, jack-o'-lanterns are a beloved symbol of Halloween festivities.