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

Keep scrolling for more

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


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

These stains had the look of overflowing effluent, rotted in the sun and impervious to power washing. Spencer Kornhaber, The Atlantic, "The Star Wars Park Is a Space-Junk Fantasy," 5 June 2019 The most serious infractions revealed in the audit include plants that exceed the volume and quality of fish-processing effluent discharged to open water allowed under the permits. Anchorage Daily News, "Audit finds 70 percent of British Columbia fish-processing plants do not comply with environmental regulations," 8 July 2018 The videographer, Tavish Campbell, spokesman for Wild First, is an opponent of open-net-pen salmon farms and contends the effluent is harmful to wild salmon. Anchorage Daily News, "Audit finds 70 percent of British Columbia fish-processing plants do not comply with environmental regulations," 8 July 2018 Years of poorly controlled antibiotic use in humans and animals, combined with effluent from the local drug industry that turned lakes and streams into breeding grounds for resistance, has left India with few weapons to fight infection. Ari Altstedter, Bloomberg.com, "The Startups Waging War Against Superbugs," 25 June 2018 The practice involves housing thousands of hogs together, flushing their waste into holding pits, allowing bacteria to break down the material, then spraying the effluent onto fields with agricultural spray guns. Fox News, "Hog farm's neighbors awarded $50M after suing over smells, spraying," 3 June 2018 Faucets are running dry and the lakes that once nurtured the southern city of Bangalore and its nearly 10 million residents are either parched or fetid with industrial waste and toxic effluents. Washington Post, "Water mismanagement leaves India’s Silicon Valley parched," 16 May 2018 Wastewater from this service area is conveyed to the San Vicente Water Reclamation Plant for treatment and effluent disposal as part of the district’s sewer service. Julie Gallant, Ramona Sentinel, "Directors raise recycled water rates to reflect cost," 11 Apr. 2018 In reaching their conclusion, the study authors compared effluent — which is wastewater that is sent into rivers and other natural bodies of water — from 13 treatment plants that took pharmaceutical discharges and six plants that did not. Ed Silverman, STAT, "Pharmaceutical manufacturing plants are sending lots of medicine into the water supply," 23 May 2018

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.

See More

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

Keep scrolling for more

Learn More about effluent

Statistics for effluent

Look-up Popularity

Time Traveler for effluent

The first known use of effluent was in 1726

See more words from the same year

Keep scrolling for more

More Definitions for effluent



English Language Learners Definition of effluent

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

Keep scrolling for more

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

Comments on effluent

What made you want to look up effluent? Please tell us where you read or heard it (including the quote, if possible).


to form ideas or theories about something

Get Word of the Day daily email!

Test Your Vocabulary

Farm Idioms Quiz

  • cow coming home
  • What does 'poke' refer to in the expression 'pig in a poke'?
Name That Thing

Test your visual vocabulary with our 10-question challenge!

Bee Cubed

Test Your Knowledge - and learn some interesting things along the way.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!