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
His neuroses flitter around him like fireflies.
—
Stephanie Zacharek, Time, 24 Oct. 2025
In the house, they’re represented as starry lights, a firefly painting (Windham was an avid painter), and a full-size Firefly scareactor.
—Eve Chen, USA Today, 16 Oct. 2025
The beneficial insects, like butterflies, moths, fireflies, and native bees, that pollinate your garden throughout the growing season require leaf litter to survive.
—Mary Marlowe Leverette, Southern Living, 4 Oct. 2025
There were fireflies everywhere.
—Tomás Mier, Rolling Stone, 3 Oct. 2025
See All Example Sentences for firefly
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Stephanie Zacharek, Time, 24 Oct. 2025
In the house, they’re represented as starry lights, a firefly painting (Windham was an avid painter), and a full-size Firefly scareactor.
—Eve Chen, USA Today, 16 Oct. 2025
The beneficial insects, like butterflies, moths, fireflies, and native bees, that pollinate your garden throughout the growing season require leaf litter to survive.
—Mary Marlowe Leverette, Southern Living, 4 Oct. 2025
There were fireflies everywhere.
—Tomás Mier, Rolling Stone, 3 Oct. 2025
See All Example Sentences for firefly
Cite this Entry
“Firefly.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/firefly. Accessed 29 Oct. 2025.
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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