Word of the Day:

February 10, 2023

ignis fatuus

noun IG-nis FATCH-uh-wus

What it Means

An ignis fatuus is a light that sometimes appears in the night over marshy ground and is often attributable to the combustion of gas from decomposed organic matter. The term can also refer to a deceptive goal or hope.

// An ignis fatuus hovered above the horizon as we made our late trek home.

// The film explores how people fall victim to the ignis fatuus of religious cults.

See the entry

Ignis fatuus in Context

"The flickering lights that led superstitious voyagers astray are not mere legends. So-called ignis fatuus, or 'foolish fire,' is a real phenomenon: a ball of flame that hovers above a marsh’s dark, still water for a few minutes before dissipating into the night." — Benji Jones, Popular Science, 31 Oct. 2018

More example sentences

Test Your Vocabulary with M-W Games & Quizzes

QUIZ Word Builder Quiz Vol. 2 Pick the letter that when added to a word will make a new word. Rinse and repeat.

QUIZ Wordmaxxing Slang Quiz Give your vocabulary a glow up by getting sendy with these questions about slang.

Latest Quizzes

Did You Know?

Ignis fatuus is a Latin term meaning, literally, "foolish fire." Other names for this light are jack-o'-lantern and will-o'-the-wisp—both of which are connected to folklore about mysterious men, Jack and Will, who carry a lantern or a wisp of light at night. A Scottish name for ignis fatuus is spunkie, from spunk, meaning "spark" or "a small fire." It has also been told that ignes fatui (the Latin plural form) are roaming souls. No doubt these stories spooked listeners by candlelight, but in time, advancements in science not only gave us electricity to dispel the darkness but proved ignis fatuus to be a visible exhalation of gas from the ground, which is rarely seen today.