flea
Americannoun
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any of numerous small, wingless bloodsucking insects of the order Siphonaptera, parasitic upon mammals and birds and noted for their ability to leap.
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either of two common fleas of the genus Ctenocephalides, the very small, black C. felis cat flea or the similar but larger C. canis dog flea, both of which infest cats, dogs, and occasionally humans.
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any of various small beetles and crustaceans that leap like a flea or swim in a jumpy manner, as the water flea and beach flea.
idioms
noun
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any small wingless parasitic blood-sucking insect of the order Siphonaptera , living on the skin of mammals and birds and noted for its power of leaping
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any of various invertebrates that resemble fleas, such as the water flea and flea beetle
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informal a sharp rebuke
Other Word Forms
Noun Inflected Forms
Etymology
Origin of flea
before 900; Middle English fle, Old English flēah, flēa; cognate with German Floh; akin to flee
Explanation
A flea is a tiny biting insect that's especially common on dogs. If you find one flea in your dog's fur, there may be hundreds more hiding in there. Fleas live by sucking blood from a host — they're parasites. You can just barely see a flea with the naked eye, and when you do spot one it may be hopping, since they're known to jump, sometimes from one animal to another. Flea bites are itchy, and fleas can be tricky to get rid of once they've laid eggs on your dog (or in your bed). Some experts think the word's root s the Old English fleon, "to flee."
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.
See Examples For:
The hardworking mother of three daughters called Los Angeles home and collected much of the material for her work from the city’s many flea markets and second hand shops.
From Los Angeles Times ● Jul. 28, 2026
When she was eventually rescued, she had lost lots of fur because of a severe flea infestation and was underweight.
From BBC ● Jul. 1, 2026
She said testing had not detected flea treatment products in treated drinking water.
From BBC ● May 3, 2026
“They called them flea pits because you caught diseases there.”
From Los Angeles Times ● Apr. 8, 2026
I told him a lot about Baba, his job, the flea market, and how, at the end, he’d died happy.
From "The Kite Runner" by Khaled Hosseini
Rodents can harm people through bites and scratches as well as their urine, droppings and fleas.
From BBC ● May 2, 2026
Scott: We did a nice dinner down by the beach, and everyone got bit by the sand fleas that weren’t supposed to be there.
From The Wall Street Journal ● Apr. 6, 2026
Often, people are exposed to the disease when infected fleas are carried indoors on pets or other animals.
From Los Angeles Times ● Apr. 3, 2026
In the Middle Ages, rats served as the reservoir for Y. pestis, while fleas acted as the vector that spread the bacterium.
From Science Daily ● Mar. 7, 2026
“No. We haven’t. We’re just living on the edge of somebody else’s, like fleas on a dog’s back. If the dog drowns, the fleas drown, too.”
From "Mrs. Frisby and the Rats of NIMH" by Robert C. O'Brien
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.
