unilateral

adjective

uni·​lat·​er·​al ˌyü-ni-ˈla-tə-rəl How to pronounce unilateral (audio)
-ˈla-trəl
Synonyms of unilateralnext
1
a
: done or undertaken by one person or party
a unilateral cease-fire
b
: of, relating to, or affecting one side of a subject : one-sided
c
: constituting or relating to a contract or engagement by which an express obligation to do or forbear is imposed on only one party
2
a
: having parts arranged on one side
a unilateral raceme
b
: occurring on, performed on, or affecting one side of the body or one of its parts
unilateral exophthalmos
3
4
: having only one side
unilaterally adverb

Did you know?

The world is a smaller place than it used to be, and we get uncomfortable when a single nation adopts a policy of unilateralism—that is, acting independently with little regard for what the rest of the world thinks. A unilateral invasion of another country, for instance, usually looks like a grab for power and resources. But occasionally the world welcomes a unilateral action, as when the U.S. announced unilateral nuclear-arms reductions in the early 1990s. Previously, such reductions had only happened as part of bilateral ("two-sided") agreements with the old Soviet Union. Multilateral agreements, on issues such as climate change, often involve most of the world's nations.

Examples of unilateral in a Sentence

Our country is prepared to take unilateral action.
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
At the same time, unilateral strikes without the consent of Congress and the American people are the wrong way to neutralize the threat of the Iranian regime. Derek Tran, Oc Register, 6 Mar. 2026 Lawmakers are confronting the sudden reality of representing wary Americans in wartime and all that entails — with lives lost, dollars spent and alliances tested by a president’s unilateral decision to go to war with Iran. Lisa Mascaro, Chicago Tribune, 5 Mar. 2026 Obama’s adoption of this legal theory opened the door for any president to engage in acts of war conducted from the air and claim that the War Powers Resolution does not apply — in other words, unilateral presidential war-making became de facto legal under the Obama position. Noah Feldman, Twin Cities, 5 Mar. 2026 Congress has not formally declared war since the Second World War, as the executive branch, under Presidents of both parties, has asserted ever-increasing authority to engage in the unilateral use of military force. Ruth Marcus, New Yorker, 5 Mar. 2026 See All Example Sentences for unilateral

Word History

First Known Use

1802, in the meaning defined at sense 1a

Time Traveler
The first known use of unilateral was in 1802

Cite this Entry

“Unilateral.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/unilateral. Accessed 10 Mar. 2026.

Kids Definition

unilateral

adjective
uni·​lat·​er·​al ˌyü-ni-ˈlat-ə-rəl How to pronounce unilateral (audio)
-ˈla-trəl
: done or carried out by only one of two or more parties
unilateral disarmament
unilaterally
adverb

Medical Definition

unilateral

adjective
uni·​lat·​er·​al ˌyü-ni-ˈlat-ə-rəl, -ˈla-trəl How to pronounce unilateral (audio)
: occurring on, performed on, or affecting one side of the body or one of its parts
unilateral exophthalmos
unilaterally adverb

Legal Definition

unilateral

adjective
uni·​lat·​er·​al ˌyü-nə-ˈla-tə-rəl How to pronounce unilateral (audio)
1
: done or undertaken by one party
a unilateral mistake as to the terms
2
: of, relating to, or affecting one side of a subject
3
: containing a promise to perform made by only one party especially because the other has already performed (as by paying an amount)
an option contract is unilateral
unilaterally adverb

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