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
Let not the magic arts of that worthless Sanford lead you, like an ignis fatuus from the path of rectitude and virtue!
And yet they say that the ignis fatuus (as it is called), which sometimes even settles on a wall, has not much heat, perhaps as much as the flame of spirit of wine, which is mild and soft.
When thou rannest up Gadshill in the night to catch my horse, if I did not think thou hadst been an ignis fatuus or a ball of wildfire, there's no purchase in money.
It appears, however, that of all flame that of spirit of wine is the softest, unless perhaps ignis fatuus be softer, and the flames or sparklings arising from the sweat of animals.