flatten
Americanverb (used with object)
verb (used without object)
verb phrase
-
flatten out to fly into a horizontal position, as after a dive.
-
flatten in flat.
verb
-
(sometimes foll by out) to make or become flat or flatter
-
informal (tr)
-
to knock down or injure; prostrate
-
to crush or subdue
failure will flatten his self-esteem
-
-
Usual US word: flat. (tr) music to lower the pitch of (a note) by one chromatic semitone
-
to manoeuvre an aircraft into horizontal flight, esp after a dive
Other Word Forms
Derived Forms
Conjugated Forms
Present
-
has flattenedperfect 3rd person singular
-
have flattenedperfect
-
is flatteningprogressive 3rd person singular
-
has been flatteningperfect progressive 3rd person singular
-
am flatteningprogressive 1st person singular
-
are flatteningprogressive
-
have been flatteningperfect progressive
-
flatteningparticiple
-
flattenssingular 3rd person
Past
-
had flattenedperfect
-
had been flatteningperfect progressive
-
was flatteningprogressive singular
-
were flatteningprogressive plural
-
flattenedparticiple
-
flattenedsimple
Future
Etymology
Origin of flatten
Explanation
When you flatten something, you crush it or level it out. If the recycling bin is getting full, you should probably flatten all those cans you're adding to it. You might flatten the batter in a cake pan before baking it, or flatten the grass along a path through a field. If your curly hair tends to get frizzy in humid weather, you may try to flatten it before you leave for school in the morning. You also might flatten yourself against a wall if you're hiding from your friend, or describe a terrible storm this way: "The tornado managed to flatten several buildings."
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
It is also encouraging to see the long-term 200-week simple moving average beginning to flatten, a potential sign that the broader downtrend is stabilizing.
From Barron's • May 27, 2026
As demand for artificial intelligence skyrockets, AI companies have been grasping for solutions to flatten the steep cost curve of compute.
From MarketWatch • Apr. 18, 2026
Long-end Treasury yields declined more than short-end yields, causing the curve to flatten.
From The Wall Street Journal • Apr. 15, 2026
Moderate relief is in sight this weekend, however, when forecasters predict the powerful high pressure system will start to flatten out, bringing a gradual drop in temperatures.
From Los Angeles Times • Mar. 19, 2026
It takes up zero space, so there is no outer edge, no place where space begins to flatten out again.
From "Zero: The Biography of a Dangerous Idea" by Charles Seife
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
