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

This allows moths, bats, fireflies, and other nocturnal insects to locate flowers for feeding and pollination efficiently. —Mary Marlowe Leverette, Southern Living, 15 June 2025

Experience glowing waves, firefly forests, and more with these breathtaking bioluminescence tours. —Alexandra Gillespie, Outside Online, 28 Apr. 2025

Bulb size and shape Fairy lights are iconic for their tiny lights that give off a glow similar to fireflies on a warm summer evening. —Bestreviews, Chicago Tribune, 27 May 2025

Goree remembers her town through images of crickets singing and fireflies lighting up the night sky. —Ignacio Calderon, USA Today, 23 May 2025

Word History

First Known Use

1655, in the meaning defined above

Rhymes for firefly

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

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