unilateral

adjective

uni·​lat·​er·​al ˌyü-ni-ˈla-tə-rəl How to pronounce unilateral (audio)
-ˈla-trəl
1
a
: done or undertaken by one person or party
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.
Investigators focused on an April 22, 2017, New York Times article about Comey’s unilateral decision to announce the outcome of the Clinton case. Kaelan Deese, The Washington Examiner, 30 Oct. 2025 Despite a higher number of abstentions than in previous years, a majority of nations – 165 – still voted in favor of lifting the decades-old embargo, citing concerns about unilateral sanctions. Nora Gámez Torres, Miami Herald, 29 Oct. 2025 Last month, Duffy warned European governments against imposing unilateral restrictions on transatlantic travel, saying Washington is prepared to enforce international agreements — a stance underscored by recent action taken against Mexico over similar concerns. David Shepardson, USA Today, 29 Oct. 2025 The judges in each of those appeals ultimately ruled that the president has the power to federalize the state’s National Guard, but does not have unilateral power to deploy the troops. Dan Gooding, MSNBC Newsweek, 29 Oct. 2025 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 31 Oct. 2025.

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

More from Merriam-Webster on unilateral

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