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

On Friday evening, before the show began, adults could be seen lounging on lawn chairs or picnic blankets across McCullough Park’s lawn while children ran around and played, some trying to catch fireflies that lit up like miniature versions of the fireworks to come. —R. Christian Smith, Chicago Tribune, 10 July 2025

For many of us, summer means attending backyard barbecues, laughing with neighbors and friends, watching kids chase fireflies, and enjoying fireworks lighting up the night. —Ashish Jha, Time, 3 July 2025

Many of us will now be spending significantly more time enjoying the great outdoors by hitting the beach, swimming, hiking, or cooking outside among the fireflies. —Laura Baisas, Popular Science, 22 May 2025

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

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