Illustration of firefly
firefly
noun
fire·fly
ˈfī(-ə)r-ˌflī 
: any of various winged nocturnal beetles (especially family Lampyridae) that produce a bright soft intermittent light by oxidation of luciferin especially for courtship purposes
Examples of firefly in a Sentence
Recent Examples on the Web
Photographers captured the Perseids and Geminids meteor showers, a giant fireball streaking across the Florida coastline, and the Milky Way glowing above thousands of fireflies in Italy.
—
Jamie Carter, Forbes.com, 17 May 2026
Rangers lead synchronous firefly viewing tours in the late summer to help travelers safely watch as nature’s magic unfolds.
—Stephanie Vermillion, Travel + Leisure, 9 May 2026
The fireflies thrive in hardwood forest environments, like Grandfather Mountain.
—Eva Flowe
may 6, Charlotte Observer, 6 May 2026
After dinner, kids ran on the main lawn catching fireflies.
—Erika Ebsworth-Goold, Midwest Living, 6 May 2026
See All Example Sentences for firefly
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Jamie Carter, Forbes.com, 17 May 2026
Rangers lead synchronous firefly viewing tours in the late summer to help travelers safely watch as nature’s magic unfolds.
—Stephanie Vermillion, Travel + Leisure, 9 May 2026
The fireflies thrive in hardwood forest environments, like Grandfather Mountain.
—Eva Flowe
may 6, Charlotte Observer, 6 May 2026
After dinner, kids ran on the main lawn catching fireflies.
—Erika Ebsworth-Goold, Midwest Living, 6 May 2026
See All Example Sentences for firefly
Cite this Entry
“Firefly.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/firefly. Accessed 27 May. 2026.
Copy CitationKids Definition
firefly
noun
fire·fly
ˈfī(ə)r-ˌflī
: any of numerous night-flying beetles that produce a bright soft flashing light for courtship purposes
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