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

Illustration of firefly

Examples of firefly in a Sentence

Recent Examples on the Web

But stars aren’t the only things that fail to show up when the sky is polluted with light; fireflies, those flashing, nostalgic symbols of summer, often skip the party too. — Evie Carrick, Travel + Leisure, 1 July 2026

There's something so soothing about sitting on the porch on a summer evening, listening to the sound of crickets and watching fireflies. — Brandee Gruener, Southern Living, 26 June 2026

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

Word History

First Known Use

1655, in the meaning defined above

Rhymes for firefly

• abscissae
• adonai
• alibi
• alkali
• alumni
• amoebae
• amplify
• annuli
• beautify
• brachii
• butterfly
• calculi

Kids 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