firefly

noun fire·fly \ ˈfī(-ə)r-ˌflī \

|Updated on: 1 Aug 2018

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

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Recent Examples of firefly from the Web

Both males and females flicker, and every species of firefly has evolved a unique code to help potential mates cut through the noise.

— katherine j. wu, Smithsonian, "Why Bioluminescence Evolved to Be Red Light, and Blue," 26 June 2018
Plant Native Pine Trees One of the biggest threats to fireflies is habitat loss.

— rebecca straus, Good Housekeeping, "6 Ways To Attract Fireflies To Your Yard," 9 June 2016
This is akin to how a firefly or a glow-stick generates its light.

— kevin davenport, idahostatesman, "O say can you see? The science behind the booms and blooms of Independence Day fireworks," 3 July 2018
These glowing bugs tend to be called fireflies in the South and lightning bugs in the Midwest.

— kathryn prociv, Washington Post, "Fireflies photobomb the Milky Way like a mischievous child with neon paint," 22 June 2018
The primary firefly love language is light, and courtship is an appropriately flashy process.

— katherine j. wu, Smithsonian, "Why Bioluminescence Evolved to Be Red Light, and Blue," 26 June 2018
Go in early summer to catch the exceptional synchronous fireflies that light up the night sky for a week or two each year.

— megan michelson, Outside Online, "6 Under-the-Radar National Parks You Should Visit," 20 June 2018
As a child, Mrs. Tallent won a contest related to collecting fireflies — something that became a lifelong interest.

— frederick n. rasmussen, baltimoresun.com, "Kathleen E. 'Kitty' Tallent, teacher, librarian, lay leader in Sisters of Mercy," 18 June 2018
The fireflies in her region are a little different.

— kaitlyn schallhorn, Fox News, "Thousands of fireflies light up US national parks with 'magical' synchronized mating ritual," 22 May 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.