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 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 This method evaluates the cost of providing recycled water by only including the costs in excess of those incurred for secondary wastewater treatment and borne as a cost of effluent disposal. Julie Gallant, Ramona Sentinel, "Directors raise recycled water rates to reflect cost," 11 Apr. 2018 Recent Examples on the Web: Noun In the effluent from the Morgantown wastewater plant, the USGS team found high concentrations of three drugs in addition to phenytoin. Natasha Gilbert, STAT, "‘Dump it down the drain’: How contaminants from prescription-drug factories pollute waterways," 11 Dec. 2019 PCBs, as they were known, were present in industrial effluent and rain and were accumulating in the tissues of fish. Keith Schneider, New York Times, "Lee Botts, Champion of the Great Lakes, Is Dead at 91," 17 Oct. 2019 They’ve also used treated wastewater from Sierra Vista’s treatment plant, where the effluent soaks into the soil to replenish groundwater. AZCentral.com, "It's one of Arizona's most precious rivers. Hundreds of new wells may leave it running dry," 5 Dec. 2019 Rapid growth and urbanisation have converted most of the wetlands into dumpyards or sites for discharge of industrial effluents. Bahar Dutt, Quartz India, "Two Indian cities lead the way in transforming concrete jungles into real jungles," 22 Oct. 2019 Due to the rain, the San Vicente Water Reclamation Plant’s effluent has been retained in on-site storage ponds to prevent unauthorized discharges. Julie Gallant, Ramona Sentinel, "RMWD pursues untreated water study, spray field bids," 5 Sep. 2019 Tiny particles of plastic get into our drinking water in a number of ways but mainly through surface runoff after rain or snow, waste water and industrial effluent. Katie Hunt, CNN, "Microplastics in drinking water 'don't appear to pose health risk,' WHO says," 21 Aug. 2019 When her grandfather was in charge, local government officials lied to him in their efforts to secure the rights to Boat Harbour — a valuable resource for the indigenous community — to use it for pulp effluent, or liquid waste, from a nearby mill. Mahita Gajanan, Time, "Watch the First Clip From Ellen Page and Ian Daniel's New Documentary About Environmental Racism," 6 Sep. 2019 Plastic waste and industrial effluent too choke India’s holy river. Paul Salopek, National Geographic, "India’s holiest river is drying up," 9 Aug. 2019

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.” The Merriam-Webster.com Dictionary, Merriam-Webster Inc., https://www.merriam-webster.com/dictionary/effluent. Accessed 18 January 2020.

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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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More from Merriam-Webster on effluent

Rhyming Dictionary: Words that rhyme with effluent

Spanish Central: Translation of effluent

Nglish: Translation of effluent for Spanish Speakers

Britannica English: Translation of effluent for Arabic Speakers

Britannica.com: Encyclopedia article about effluent

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