A yule log is a large piece of wood traditionally burned in the fireplace during Christmas celebrations. The custom comes from ancient winter festivals in Northern Europe, where families would bring in the biggest log they could find, light it on Christmas Eve, and keep it burning for the twelve days of Christmas. People believed the log brought good luck and warmth during the coldest, darkest time of year.

The tradition evolved over centuries. Families would save a piece of the previous year's log to light the new one, connecting each Christmas to the last. In some places, people decorated the log with evergreen branches and ribbons before burning it. As fireplaces became less common in homes, the yule log transformed into something you could eat instead of burn: a bûche de Noël, a Christmas cake shaped and decorated to look like a log, complete with bark-like chocolate frosting and sometimes marzipan mushrooms.

Today, when people talk about a yule log, they might mean the actual burning log (still a tradition in some families), the chocolate cake, or even videos of a fireplace playing on TV during the holidays.