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

Japanese is a high-context language, meaning that more can be conveyed with less; an English translation naturally bloats the word count and flattens the cultural context. — Literary Hub, 13 July 2026

But at least on paper, average rents have essentially flattened, not lowered, over the past three years. — Michael Smolens, San Diego Union-Tribune, 12 July 2026

Even then, the town still needs to prepare for a future where Neil may become three times his current size – and capable of flattening more than a traffic cone. — Jessie Yeung, CNN Money, 11 July 2026

Trade-offs that deserve nuance get flattened into false binaries. — Joy Nissen, Forbes.com, 10 July 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