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
And every spring, thousands of people throw their names into a lottery for a chance to witness synchronous fireflies in the Smokies.
—
Usa Today Network, USA Today, 10 June 2026
In one, raindrops spark like fireflies against a marsh muted by a storm.
—Amy Paige Condon, AJC.com, 10 June 2026
Contributing to Firefly Conservation One of the best ways to contribute to firefly conservation is to create a thriving firefly habitat in your garden.
—Mary Marlowe Leverette, Southern Living, 6 June 2026
The park is home to Photinus carolinus fireflies, just like the Smokies, as well as the enchanting blue ghost fireflies (Phausis reticulata), which emit a blue-green glow.
—Stephanie Vermillion, Travel + Leisure, 9 May 2026
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Usa Today Network, USA Today, 10 June 2026
In one, raindrops spark like fireflies against a marsh muted by a storm.
—Amy Paige Condon, AJC.com, 10 June 2026
Contributing to Firefly Conservation One of the best ways to contribute to firefly conservation is to create a thriving firefly habitat in your garden.
—Mary Marlowe Leverette, Southern Living, 6 June 2026
The park is home to Photinus carolinus fireflies, just like the Smokies, as well as the enchanting blue ghost fireflies (Phausis reticulata), which emit a blue-green glow.
—Stephanie Vermillion, Travel + Leisure, 9 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 15 Jun. 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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