Definition & Meaning of "will-o'-the-wisp"

What is a "will-o'-the-wisp"?

A will-o'-the-wisp is a mythical phenomenon often depicted as a mysterious light that appears at night in marshes or swamps. This glowing light is usually described as hovering above the ground and moving unpredictably. In folklore, will-o'-the-wisps are believed to be mischievous spirits or supernatural entities that lead travelers astray, causing them to become lost or confused. The phenomenon is sometimes attributed to natural causes, such as gases emitted from decaying organic matter, but in mythology, it represents the idea of deceptive appearances and the dangers of being misled.