Ĭg'nis-fāt'ū-ŭs, n.

n.; pl. Ĭg'NĒS-FĀT'Ē-Ī. [Lat. ignis, fire, and fatuus, foolish; — so called in allusion to its tendency to mislead travelers.] A meteor or light that appears, in the night, over marshy grounds, supposed to be occasioned by the decomposition of animal or vegetable substances, or by some inflammable gas; — popularly called also Will-with-the-wisp, or Will-o’-the-wisp, and Jack-with-a-lantern, or Jack-a-lantern.