ignis fatuus

ig·​nis fat·​u·​us | \ ˈig-nəs-ˈfa-chə-wəs How to pronounce ignis fatuus (audio) , -ˈfach-wəs \
plural ignes fatui\ ˈig-​ˌnēz-​ˈfa-​chə-​ˌwī How to pronounce ignis fatuus (audio) \

Definition of ignis fatuus

1 : a light that sometimes appears in the night over marshy ground and is often attributable to the combustion of gas from decomposed organic matter
2 : a deceptive goal or hope

Examples of ignis fatuus in a Sentence

Recent Examples on the Web The story also helped explain ignis fatuus, a natural phenomenon that occurs in marshlands and bogs—such as those in Ireland’s countryside—producing flickering lights as gases from decomposing organic matter combust. National Geographic, 27 Oct. 2020

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'ignis fatuus.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of ignis fatuus

1563, in the meaning defined at sense 1

History and Etymology for ignis fatuus

Medieval Latin, literally, foolish fire

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The first known use of ignis fatuus was in 1563

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Cite this Entry

“Ignis fatuus.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/ignis%20fatuus. Accessed 1 Jul. 2022.

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