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

Then in 1999, alleging that related terrorist bombings had continued, Russia again invaded in a second war that would flatten capital city Grozny and kill thousands more people. —Arizona Republic, AZCentral.com, 11 Dec. 2025

Companies including Amazon, Moderna, and McKinsey are already eliminating management layers, working to flatten organizations, and deploying AI agents to automate routine work. —Beatrice Nolan, Fortune, 10 Dec. 2025

These knockoffs flatten years of heritage, intention, and artistry into a quick-selling aesthetic. —Mecca Pryor, Essence, 9 Dec. 2025

Then there’s Paul Bunyan Sugar Cookies, which, fear not, are nowhere near as big as his mythical flapjacks, and Bright-Eyed Susans, a version of a thumbprint cookie, here, flattened in the center with a chocolate-mint candy wafer. —Alana Al-Hatlani, Southern Living, 7 Dec. 2025

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