flatten

verb

flat·​ten ˈfla-tᵊn 

flattened; flattening ˈflat-niŋ 

ˈfla-tə-

transitive verb

: to make flat

flatten the dough into a disk

The dog flattened its ears.

: such as

a

: to make level or smooth

flattened the papers

b

: to knock down

houses flattened by the tornado

also : to defeat decisively

got flattened in the first round of playoffs

c

: to make dull or uninspired

… small changes … that flatten a writer's style …

—John Gross

—often used with out

In thus flattening out a complicated story, the book misses an opportunity …

—Tony Judt

d

: to make lusterless

flatten paint

e

: to stabilize especially at a lower level

a candidate promising to flatten interest rates

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

prices flattening out

flattener

ˈflat-nər 

ˈfla-tə-

noun

Synonyms of flatten

• smooth

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.

Recent Examples on the Web

Even with an over route that, under very few scenarios becomes part of the progression, Moore should have stayed full throttle and recognized the leverage in the secondary to flatten his route. — Dan Wiederer, New York Times, 7 Sep. 2026

Shaving down the error Instead of building costly new equipment, the team solved the issue by flattening the material’s surface using a Cooling Cross-section Polisher. — Mrigakshi Dixit, Interesting Engineering, 7 Sep. 2026

Zumthor’s discussion of creating inner security and safety for me immediately evokes for me the specter of its opposite, the unsafe spaces, the spaces of destruction, the homes flattened in Ukraine, Yemen, Lebanon and Gaza. — Scott Roxborough, HollywoodReporter, 6 Sep. 2026

They have all been flattened, overwritten by the wall of mud and water that claimed everything in its path. — Simone McCarthy, CNN Money, 6 Sep. 2026

Word History

First Known Use

1630, in the meaning defined at transitive sense

Rhymes for flatten

• batten
• craton
• fatten
• gratin
• gratton
• latin
• lattin
• matin
• paten
• patten
• platen
• ratan

Kids Definition

flatten

verb

flat·​ten ˈflat-ᵊn 

flattened; flattening ˈflat-niŋ 

-ᵊn-iŋ

: to make or become flat