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ignis fatuus

[ig-nis fach-oo-uh s] /ˈɪg nɪs ˈfætʃ u əs/
noun, plural ignes fatui
[ig-neez fach-oo-ahy] /ˈɪg niz ˈfætʃ uˌaɪ/ (Show IPA)
Also called friar's lantern, will-o'-the-wisp. a flitting phosphorescent light seen at night, chiefly over marshy ground, and believed to be due to spontaneous combustion of gas from decomposed organic matter.
something deluding or misleading.
1555-65; < Medieval Latin: literally, foolish fire Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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British Dictionary definitions for ignis-fatuus

ignis fatuus

/ˈɪɡnɪs ˈfætjʊəs/
noun (pl) ignes fatui (ˈɪɡniːz ˈfætjʊˌaɪ)
another name for will-o'-the-wisp
Word Origin
C16: from Medieval Latin, literally: foolish fire
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
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Word Origin and History for ignis-fatuus

ignis fatuus


"will o' the wisp, jack-a-lantern," 1560s, from Medieval Latin, literally "foolish fire;" see igneous + fatuous.

Online Etymology Dictionary, © 2010 Douglas Harper
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Encyclopedia Article for ignis-fatuus

ignis fatuus

in meteorology, a mysterious light seen at night flickering over marshes; when approached, it advances, always out of reach. The phenomenon is also known as will-o'-the-wisp and ignis fatuus (Latin: "foolish fire"). In popular legend it is considered ominous and is often purported to be the soul of one who has been rejected by hell carrying its own hell coal on its wanderings. The phenomenon is generally believed to be due to the spontaneous ignition of marsh gas, which consists mostly of methane and which is produced by the decomposition of dead plant matter

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Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
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