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
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New research published in BMC Genomics looks at the genetics of the common eastern firefly (Photinus pyralis) and found that besides bioluminescent flashes, fireflies may also be using pheromones to attract mates.
—
Monica Cull, Discover Magazine, 18 July 2025
The couple noted the uptick in fireflies this summer before Consuelos went in depth on the insect species' mating ritual.
—EW.com, 11 July 2025
Experts also know fireflies face growing threats to their habitat and survival.
—Connor Giffin, The Courier-Journal, 3 July 2025
On Friday evening, before the show began, adults could be seen lounging on lawn chairs or picnic blankets across McCullough Park’s lawn while children ran around and played, some trying to catch fireflies that lit up like miniature versions of the fireworks to come.
—R. Christian Smith, Chicago Tribune, 10 July 2025
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Monica Cull, Discover Magazine, 18 July 2025
The couple noted the uptick in fireflies this summer before Consuelos went in depth on the insect species' mating ritual.
—EW.com, 11 July 2025
Experts also know fireflies face growing threats to their habitat and survival.
—Connor Giffin, The Courier-Journal, 3 July 2025
On Friday evening, before the show began, adults could be seen lounging on lawn chairs or picnic blankets across McCullough Park’s lawn while children ran around and played, some trying to catch fireflies that lit up like miniature versions of the fireworks to come.
—R. Christian Smith, Chicago Tribune, 10 July 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 19 Aug. 2025.
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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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