Definition of ignis fatuus in English:

ignis fatuus

noun

  • A will-o'-the-wisp.

    • ‘But it's impossible to describe these paintings, also because they hit your soul like burning arrows and recall the sad and reddish dance of the ignis fatuuses.’
    • ‘How is the gas of ignis fatui ignited on bogs and meadows?’
    mirage, hallucination, apparition, phantasm, phantom, vision, spectre, fantasy, figment of the imagination, will-o'-the-wisp, trick of the light
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Origin

Mid 16th century: modern Latin, literally foolish fire (because of its erratic movement).

Pronunciation:

ignis fatuus

/ˌɪɡnɪs ˈfatjʊəs/