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

Distant lights – maybe car lights or fireflies – dance across a pitch-black night scene. — John Hopewell, Variety, 18 Sep. 2026

For children themselves, wonder remains abundant—in the bigness of a Tyrannosaurus rex in a museum, or the flicker of fireflies in the summer dusk. — Ian Bogost, The Atlantic, 4 Sep. 2026

Think of Roman as being able to take a picture of a firefly next to a floodlight from the other side of the country, Domagal-Goldman said. — Ashley Strickland, CNN Money, 30 Aug. 2026

That’s harder than trying to spot a firefly right next to someone flashing their high-beams at you. — Noah Haggerty, Los Angeles Times, 28 Aug. 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