from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A phosphorescent light that hovers or flits over swampy ground at night, possibly caused by spontaneous combustion of gases emitted by rotting organic matter. Also called friar's lantern, jack-o'-lantern, will-o'-the-wisp, wisp.
- n. Something that misleads or deludes; an illusion.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A will o' the wisp.
- n. A delusion, a false hope.
from the GNU version of the Collaborative International Dictionary of English
- 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.
- Fig.: A misleading influence; a decoy.
from The Century Dictionary and Cyclopedia
- A meteoric light that sometimes appears in summer and autumn nights, and flits in the air a little above the surface of the earth, chiefly in marshy places, near stagnant waters, or in churchyards.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. an illusion that misleads
- n. a pale light sometimes seen at night over marshy ground
Medieval Latin : Latin ignis, fire + Latin fatuus, foolish.(American Heritage® Dictionary of the English Language, Fourth Edition)
Modern Latin, from ignis (meaning "fire") + fatuus (meaning "foolish"). Literally "foolish fire". (Wiktionary)