Bible Dictionaries
Ignis Fatuus

Webster's Dictionary

(1):

A phosphorescent light that appears, in the night, over marshy ground, 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-o'-lantern.

(2):

Fig.: A misleading influence; a decoy.

Bibliography Information
Webster, Noah. Entry for 'Ignis Fatuus'. Noah Webster's American Dictionary. https://www.studylight.org/​dictionaries/​eng/​web/​i/ignis-fatuus.html. 1828.