fire·​fly | \ ˈfī(-ə)r-ˌflī How to pronounce firefly (audio) \

Definition of firefly

: any of various winged nocturnal beetles (especially family Lampyridae) that produce a bright soft intermittent light by oxidation of luciferin especially for courtship purposes

Illustration of firefly

Illustration of firefly

Examples of firefly in a Sentence

Recent Examples on the Web

Normally this wouldn’t be a big deal, but the fireflies were very interested in the camera and, by extension, in me. Kirsten Luce, National Geographic, "See thousands of fireflies light up a Mexican forest," 17 June 2019 Pull out the water skis, the fishing poles, the skateboards, the boats, the ball and glove, the little glass jar with holes poked in the lid for catching fireflies. Randy Blaser,, "Column: Summer is here. You better enjoy it while it lasts.," 6 June 2019 According to our guides, visitors are usually not allowed to photograph the fireflies because the presence of artificial light from electronics can affect their habits. Kirsten Luce, National Geographic, "See thousands of fireflies light up a Mexican forest," 17 June 2019 The program begins inside the lodge with a primer on firefly biology. Joan Rusek,, "Jump into summer fun with new activities galore: Valley Views," 16 June 2019 During the event, participants will learn how and why fireflies produce their light. Beacon-news Staff, Aurora Beacon-News, "Summer Concert Series to be held along Fox River in Geneva," 12 June 2019 When grass and other shrubs are at a higher level, there are more places for fireflies to create a space to live in. Elizabeth Gulino, House Beautiful, "Pine Trees Might Be the Secret to Attracting More Fireflies to Your Yard This Summer," 6 June 2019 Crickets sing in synchrony; metronomes placed side by side sway into lockstep; some fireflies blink together in the dark. Quanta Magazine, "Scientists Discover Exotic New Patterns of Synchronization," 4 Apr. 2019 Today’s first plate featured kawahagi, tilefish, topped with its own liver; toro, ultra-fatty tuna; grilled sawara, Spanish mackerel; and stewed hotari-ika, firefly squid. Tom Downey, WSJ, "A Sushi-Obsessed Trip to Osaka," 4 Dec. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'firefly.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of firefly

1655, in the meaning defined above

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Statistics for firefly

Last Updated

4 Jul 2019

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Time Traveler for firefly

The first known use of firefly was in 1655

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More Definitions for firefly



English Language Learners Definition of firefly

: a small flying insect that produces a soft light


fire·​fly | \ ˈfīr-ˌflī How to pronounce firefly (audio) \
plural fireflies

Kids Definition of firefly

: a small beetle producing a soft light

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More from Merriam-Webster on firefly

Rhyming Dictionary: Words that rhyme with firefly

Spanish Central: Translation of firefly

Nglish: Translation of firefly for Spanish Speakers

Britannica English: Translation of firefly for Arabic Speakers Encyclopedia article about firefly

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