\ ˈlau̇s How to pronounce louse (audio) \

Definition of louse

 (Entry 1 of 2)

1 plural lice\ ˈlīs How to pronounce louse (audio) \
a : any of various small wingless usually flattened insects (orders Anoplura and Mallophaga) parasitic on warm-blooded animals
b : a small usually sluggish arthropod (such as a biting louse) that lives on other animals or on plants and sucks their blood or juices
c : any of several small arthropods (such as a book louse) that are not parasitic
2 plural louses\ ˈlau̇-​səz How to pronounce louse (audio) \ : a contemptible person : heel what a beast, what a cad, what a louse he had been— Walter Karig


\ ˈlau̇s How to pronounce louse (audio) , ˈlau̇z How to pronounce louse (audio) \
loused; lousing

Definition of louse (Entry 2 of 2)

transitive verb

: to remove lice from

Synonyms for louse

Synonyms: Noun

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Examples of louse in a Sentence

Noun a problem with head lice Her ex-husband is a real louse.
Recent Examples on the Web: Noun After century phylloxera louse decimated vineyards throughout the world in the 18th century, such grafting solved this international problem. Tom Mullen, Forbes, 24 July 2022 Now, Galassi and American louse workers say, infestation rates are back to pre-lockdown norms, despite school COVID-19 protections. oregonlive, 28 Nov. 2021 An Edmontosaurus is a cozy home for a louse and its prolific, extended family—foot after foot of supple dinosaur flesh just waiting for tiny piercing mouthparts. Riley Black, Smithsonian Magazine, 26 Apr. 2022 The winery name and logo evoke the vine louse that destroyed much of Europe’s vineyards in the late 1800s. Washington Post, 3 Mar. 2022 But even a school nurse might be shocked at their real staying power; scientists have previously found louse eggs still stubbornly stuck to ancient hair after 10,000 years. Brian Handwerk, Smithsonian Magazine, 28 Dec. 2021 This shape hair is physically easier for the louse claw to attach to. Danielle James, Allure, 28 Dec. 2021 According to the park, the louse enters a fish’s mouth through its gills, severs the tongue and serves as a functioning tongue while feeding on mucus. Pete Thomas, USA TODAY, 20 Oct. 2021 But she's obsessed with the louse she's been chasing for years, and with a corpse just reeled in from the Boston Harbor. Jim Higgins, Milwaukee Journal Sentinel, 28 Nov. 2021 Recent Examples on the Web: Verb Will Ferrell figure out a way to get along, their fathers (Mel Gibson, John Lithgow) show up for the holidays to louse everything up in this comedy sequel. Chris Foran, Milwaukee Journal Sentinel, 31 Aug. 2017 See More

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'louse.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of louse


before the 12th century, in the meaning defined at sense 1a


14th century, in the meaning defined above

History and Etymology for louse

Noun and Verb

Middle English lous, from Old English lūs; akin to Old High German lūs louse, Welsh llau lice

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Time Traveler for louse

Time Traveler

The first known use of louse was before the 12th century

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Statistics for louse

Last Updated

5 Aug 2022

Cite this Entry

“Louse.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/louse. Accessed 14 Aug. 2022.

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More Definitions for louse


\ ˈlau̇s How to pronounce louse (audio) \
plural lice\ ˈlīs \

Kids Definition of louse

1 : a small, wingless, and usually flat insect that lives on the bodies of warm-blooded animals
2 : an insect or related arthropod that resembles a body louse and feeds on plant juices or decaying matter


\ ˈlau̇s How to pronounce louse (audio) \
plural lice\ ˈlīs How to pronounce louse (audio) \

Medical Definition of louse

: any of the small wingless usually flattened insects that are parasitic on warm-blooded animals and constitute the orders Anoplura and Mallophaga

More from Merriam-Webster on louse

Nglish: Translation of louse for Spanish Speakers

Britannica English: Translation of louse for Arabic Speakers

Britannica.com: Encyclopedia article about louse


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