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:
Over the counter flea treatments which are used by pet owners in the UK should be banned, a panel of vets has told a parliamentary inquiry.
From BBC ● Jun. 10, 2026
When Saar visited Milan for the exhibition opening in 2016, Barbatti took her to the local flea markets.
From Los Angeles Times ● May 7, 2026
Animal welfare remains paramount, Defra said, and continued access to effective flea and tick treatments for pet owners is a key priority.
From BBC ● Apr. 16, 2026
“They called them flea pits because you caught diseases there.”
From Los Angeles Times ● Apr. 8, 2026
“And that’s my problem? Just because he comes from the same hippie-dippie flea circus where you grew up doesn’t mean we have to adopt him!”
From "Schooled" by Gordon Korman
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
The disease spread through fleas that carried the bacterium Yersinia pestis.
From Science Daily ● Mar. 7, 2026
Mr. Kleiman sprinkled yellow powder in every nook and cranny, but the fleas haven’t taken the slightest notice.
From "The Diary of a Young Girl" by Anne Frank
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.
