firefly
Americannoun
noun
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any nocturnal beetle of the family Lampyridae , common in warm and tropical regions, having luminescent abdominal organs See also glow-worm
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any tropical American click beetle of the genus Pyrophorus , esp P. noctiluca , that have luminescent thoracic organs
Other Word Forms
Etymology
Origin of firefly
Explanation
Fireflies are flying beetles that glow in the dark. If you gently catch a firefly between your palms, you can watch its light flicker on and off for a while, and then let it go. Depending on where you live, you may call fireflies "lightning bugs" or "glowworms." There are fewer of these light-emitting insects on the planet than there used to be, but you can still find places where they gather in groups at dusk, glowing and flickering like stars. Contrary to their name, fireflies aren't flies, but instead belong to a family of beetles with an amazing ability to produce a luminous light.
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
The number of applications for parking spots at Great Smoky Mountains National Park during the annual eight-night firefly viewing period.
From The Wall Street Journal • Jun. 5, 2026
The Photinus carolinus species of firefly has just a few weeks every summer to flash their bioluminescent lights and mate.
From The Wall Street Journal • Jun. 3, 2026
“It takes the light coming from the firefly and bends it and amplifies it so we can see it in glorious detail,” he told BBC News.
From BBC • Dec. 11, 2024
Emotionally, after riding through a cavern featuring a frog-led band with a firefly chorus, all creating a rousing, sing-along take on “Dig a Little Deeper,” the mood is one of pure uplift.
From Los Angeles Times • Jun. 11, 2024
I screamed for help—and miraculously, help came, in the form of what I thought at first was a firefly, flashing as it flew toward me.
From "Miss Peregrine's Home for Peculiar Children" by Ransom Riggs
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
