flea
Americannoun
-
any of numerous small, wingless bloodsucking insects of the order Siphonaptera, parasitic upon mammals and birds and noted for their ability to leap.
-
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.
-
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
-
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
-
any of various invertebrates that resemble fleas, such as the water flea and flea beetle
-
informal a sharp rebuke
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.
She said testing had not detected flea treatment products in treated drinking water.
From BBC • May 3, 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
If I were spinning at a bar, club or flea market, I’d likely ease into my set with more chill songs before getting into bangers.
From Los Angeles Times • Apr. 15, 2026
If an old girlfriend buys you a set of cocktail glasses from a flea market, those glasses will always evoke thoughts of that person.
From Los Angeles Times • Apr. 8, 2026
The story included a couple of quotes from me—one was about Dad needing to work on his self-control, and the other was about how he wouldn’t hurt a flea.
From "Flush" by Carl Hiaasen
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.
