ef·​flu·​ent | \ ˈe-ˌflü-ənt How to pronounce effluent (audio) ; e-ˈflü-, ə- \

Definition of effluent

 (Entry 1 of 2)

: flowing out : emanating, outgoing an effluent river



Definition of effluent (Entry 2 of 2)

: something that flows out: such as
a : an outflowing branch of a main stream or lake
b : waste material (such as smoke, liquid industrial refuse, or sewage) discharged into the environment especially when serving as a pollutant

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Did You Know?

Effluent comes from the Latin verb effluere, "to flow out". In an older meaning, an effluent was a stream flowing out of a river or lake. But nowadays effluent almost always means wastes that pour into our water and air. Liquid factory waste, smoke, and raw sewage can all be called effluents. An effluent filter keeps treated waste flowing out of a septic tank from clogging up its drainage pipes.

Examples of effluent in a Sentence

Noun The factory has been accused of discharging effluent into the river.
Recent Examples on the Web: Adjective Just like wastewater from cattle or poultry farms, effluent from fish farms can be a serious pollution source. Pallab Sarker, The Conversation, "Taking fish out of fish feed can make aquaculture a more sustainable food source," 14 Dec. 2020 On a small scale, effluent from individual buildings — college dorms, prisons, nursing homes and homeless shelters — is increasingly being surveilled for coronavirus. Kim Tingley, New York Times, "Watching What Goes Down Our Toilets Could Help Keep a Pandemic From Spiraling Out of Control," 24 Nov. 2020 The wastewater disperses nearly 33 days later as highly treated effluent into marsh, through the legs of wood storks and roseate spoonbills and then to an expanse of cordgrass and sable palms of the St. Johns River. Kevin Spear, orlandosentinel.com, "Orlando’s secret life of sewers: What workers hope you never know," 18 Nov. 2020 The researchers also collected effluent from two wastewater treatment plants, which filter out some, but not all, microfibers before pumping the water into Lake Ontario. Matt Simon, Wired, "Your Beloved Blue Jeans Are Polluting the Ocean—Big Time," 2 Sep. 2020 Bees feeding on effluent streams from an M&M candy factory were producing honey that was green, red, and blue. Benjamin R. Cohen, Wired, "Your Food Isn’t ‘Natural’ and It Never Will Be," 8 Oct. 2020 Plumes from effluent pipes greased the river that ran through our town. Kerri Arsenault, The New York Review of Books, "My Eighty-Six Jobs," 1 Sep. 2020 But that facility can’t filter out all of the fibers, which flow out to sea as effluent. Matt Simon, Wired, "Wait, How Much Microplastic Is Swirling in the Atlantic?," 18 Aug. 2020 In violation of Kenyan environmental and human rights law, the factory's smelting process would emit fumes, dust, and effluent laden with lead particles, according to a 2015 report by the Ministry of Health. Deborah Bloom, CNN, "The woman risking her life to save a village from lead poisoning," 20 Apr. 2018 Recent Examples on the Web: Noun But a lot is riding on Mexico following through with plans to improve its sewage system and complete a water-recycling project that would clean up tainted effluent so it can be used to irrigate vineyards in the Guadalupe Valley. Michael Smolens Columnist, San Diego Union-Tribune, "Column: Mexico’s effort will be key in reducing sewage spills; U.S. can’t do it alone," 19 Feb. 2021 Fish effluent is transformed into a nutrient for plants, then recycled back into the fish tank. Los Angeles Times, "Growing food without dirt? Yes, you should try it at home," 21 Jan. 2021 Industry arrived in force to its shores at the turn of the twentieth century, adding chemical dumping on top of the human effluent, with the Brooklyn Yard Dye Company and the Brooklyn Union Gas Company among the worst offenders. Caroline Spivack, Curbed, "A Coney Island Baptism Spot Might Be Declared a Superfund Site," 4 Jan. 2021 Nitrogen comes from municipal and industrial wastewater effluent, failed or failing septic fields, animal waste, fertilizers and vehicular exhausts. Suzanne Baker, chicagotribune.com, "Banning some types of fertilizers and sealants will improve Naperville-area rivers, streams: Sierra Club," 24 Dec. 2020 The photos depict nature, mostly in the form of aquatic birds, accommodating itself to AlexRenew’s water-treatment lagoons and the outfall pipes where effluent can enter the river. Washington Post, "In the galleries: Up to his elbows in watery works and lustrous prints," 18 Dec. 2020 Rather, the wealthier a neighborhood, the less virus in its effluent. Kim Tingley, New York Times, "Watching What Goes Down Our Toilets Could Help Keep a Pandemic From Spiraling Out of Control," 24 Nov. 2020 The effluent is cleaner than its final destination, the St. Johns River. Kevin Spear, orlandosentinel.com, "Orlando’s secret life of sewers: What workers hope you never know," 18 Nov. 2020 Some of that fertilizer, along with effluent from cows and other animals, seeps into the rivers. Tracy Withers, Bloomberg.com, "Not-So-Green New Zealand Has a Dirty River Problem," 11 Oct. 2020

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

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First Known Use of effluent


1726, in the meaning defined above


1859, in the meaning defined above

History and Etymology for effluent


Latin effluent-, effluens, present participle of effluere to flow out, from ex- + fluere to flow — more at fluid

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Time Traveler for effluent

Time Traveler

The first known use of effluent was in 1726

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Cite this Entry

“Effluent.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/effluent. Accessed 8 Mar. 2021.

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More Definitions for effluent



English Language Learners Definition of effluent

formal : liquid (such as sewage or industrial chemicals) that is released as waste

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