flat·​ten | \ˈfla-tᵊn \
flattened; flattening\ ˈflat-​niŋ , ˈfla-​tə-​ \

Definition of flatten 

transitive verb

: to make flat: such as

a : to make level or smooth

b : to knock down also : to defeat decisively

c : to make dull or uninspired often used with out

d : to make lusterless flatten paint

e : to stabilize especially at a lower level

intransitive verb

: to become flat or flatter: such as

a : to become dull or spiritless

b : to extend in or into a flat position or form

c : to become uniform or stabilized often at a new lower level usually used with out

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Other Words from flatten

flattener \ ˈflat-​nər , ˈfla-​tə-​ \ noun

Synonyms & Antonyms for flatten


even, level, plane, smooth


rough, roughen

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Examples of flatten in a Sentence

Dozens of houses were flattened by the tornado. The boxer was flattened in the seventh round. The team got flattened in the first round of the play-offs. Prices are expected to flatten after the holiday shopping season.
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Recent Examples on the Web

Medicine has taken a page from aviation over the last decade or so, adopting practices such as checklists and flattening the hierarchies among doctors, nurses, and other clinicians in an effort to reduce medical errors. Lucas Laursen, Fortune, "Burned-Out Doctors Make Twice as Many Errors. The Business World Could Offer a Solution," 10 July 2018 China is important to Ford, and every automaker, because the market is so enormous and has considerable room for growth, while the mature U.S. market is flattening after record sales in 2016. Randy Essex, Detroit Free Press, "Ford names China leadership amid slumping sales and 'bumpy ride'," 25 Apr. 2018 Marcy has been flattened, to be specific, by the hulking weight of her senior citizen boyfriend, who has died during their secret tryst. Beth Kephart, Philly.com, "Frances Metzman's 'Cha-Cha Babes of Pelican Bay': The rules of dancing, life, and rocking thongs in a retirement village," 6 July 2018 The ball of this ball-and-socket joint had been flattened by wear and tear, and its no-longer-smooth surface was now in direct contact with the bony cup of the socket. Lisa Sanders, New York Times, "The Patient Had Pain When He Walked, but There Was a More Telling Change," 27 June 2018 Everything there will be flattened except for the Hooters on the southwest corner at Cobb Parkway and North Roberts Road. Ben Brasch, ajc, "A $65M mixed-use development is set to take over Cobb shopping center," 26 June 2018 The tires on 18 vehicles and one trailer were flattened. Lisa M. Bolton, Washington Post, "Crime reports for Anne Arundel and Howard counties and for Annapolis," 20 June 2018 Buildings among the narrow streets were bombed out while others were flattened. Mike Miller, PEOPLE.com, "How Angelina Jolie Spent Father's Day Amid Custody Drama with Brad Pitt," 18 June 2018 The two launches only went a short distance but if their astronomical trajectories were flattened out, the missiles would be capable of hitting nearly all of the United States. W.j. Hennigan, Time, "President Trump Wants North Korea to Give Up Nuclear Weapons. Here's Just How Hard That Would Be," 11 June 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'flatten.' 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 flatten

1630, in the meaning defined at transitive sense

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Statistics for flatten

Last Updated

31 Oct 2018

Look-up Popularity

Time Traveler for flatten

The first known use of flatten was in 1630

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More Definitions for flatten



English Language Learners Definition of flatten

: to make (something) flat or flatter

: to become flat or flatter

: to knock down (something or someone)


flat·​ten | \ˈfla-tən \
flattened; flattening

Kids Definition of flatten

: to make or become flat She flattened herself against the wall.

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Comments on flatten

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


obstinately defiant of authority

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