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

The actual reason the Dodgers lost, that the postseason in baseball is little more than a coin flip and small sample sizes flatten out any talent advantage, is boring and uninteresting. — Ian Miller Outkick, FOXNews.com, 23 Oct. 2026

Scoop approximately 2 tablespoons of dough per tea cake, form into small rounds, and gently flatten. — ABC News, 22 Oct. 2026

And test on mid-lengths and ends first — oils that work beautifully on one hair type can flatten another. — Lauren Jarvis-Gibson, Kansas City Star, 21 Oct. 2026

Here, his clumsy, winky, affected, and self-undercutting direction can’t even work the charming Jenna Ortega to a great performance, as her Klara is flattened into a bundle of manic pixie mannerisms both physical and verbal. — Ryan Lattanzio, IndieWire, 20 Oct. 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