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 For a magical summer trip, head to the Alleghany National Forest for an annual firefly light show. Gina Decaprio Vercesi, Travel + Leisure, 12 Apr. 2022 The news came as a surprise to Peggy and Ken Butler, whose Kellettville backyard turned out to be a hotbed of firefly activity. Gina Decaprio Vercesi, Travel + Leisure, 12 Apr. 2022 On the big day, passholders can enter the firefly viewing area at 6:30 p.m. (well after the park closes at 4 p.m.) and stay until 10 p.m. The best time to view the fireflies is just after dark, usually between 9 and 10 p.m. Evie Carrick, Travel + Leisure, 21 Mar. 2022 The sketch ends with Ray, a middle aged Cajun firefly played by Andrew Dismukes, getting eaten by the Prince. Andy Hoglund,, 13 Mar. 2022 The firefly pioneers of the twentieth century were Elisabeth and John Buck, a married couple who began methodically studying fireflies and theorizing about synchronicity in the Thirties. Vanessa Gregory, Harper’s Magazine , 16 Feb. 2022 Some of them have been to the firefly viewing several times. Leigh Ann Henion, Washington Post, 7 Sep. 2021 Hunting for an exoplanet with just a telescope, even a really big one, is as useless as looking for a firefly with a spotlight shining in your face. Chris Wright, Wired, 4 Jan. 2022 There are plenty of other ways to tap into that firefly-like glow… like actual makeup primer. Molly Longman,, 21 Nov. 2021 See More

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.

First Known Use of firefly

1655, in the meaning defined above

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Time Traveler for firefly

Time Traveler

The first known use of firefly was in 1655

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Dictionary Entries Near firefly



firefly squid

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Statistics for firefly

Last Updated

9 May 2022

Cite this Entry

“Firefly.” Dictionary, Merriam-Webster, Accessed 18 May. 2022.

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More Definitions for firefly


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

Kids Definition of firefly

: a small beetle producing a soft light

More from Merriam-Webster on firefly

Nglish: Translation of firefly for Spanish Speakers

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


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