uni·lat·er·al | \ ˌyü-ni-ˈla-tə-rəl , -ˈla-trəl \

Definition of unilateral 

1a : 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

2a : 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 : unilineal

4 : having only one side

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Other words from unilateral

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

The vote was finally held amid a violent crackdown by police sent in by Madrid, and the unilateral declaration of a new Catalan republic that followed was never implemented after central authorities seized control over the region. Aritz Parra, The Seattle Times, "Spanish, Catalan leaders meet to bridge gap over secession," 9 July 2018 What was once a one-shot meeting became the beginning of a process; the objective of unilateral disarmament was transformed into a mission of building relationships. Mira Rapp-hooper, Washington Post, "The Singapore summit’s three big takeaways," 12 June 2018 Bolton has repeatedly suggested the Libya model of unilateral disarmament for North Korea, most recently on Sunday. NBC News, "Trump seeks to placate Kim Kong Un over uncertain summit," 18 May 2018 Talking about the Winter Olympics is positive but is a long way from unilateral nuclear disarmament. Charlie Campbell / Beijing, Time, "However Small, North Korea's Olympics Talks Are a Victory," 8 Jan. 2018 Another unilateral attempt at secession is highly unlikely in the medium term. Jeannette Neumann, WSJ, "German Court Authorizes Extradition to Spain of Catalonia’s Former Leader," 12 July 2018 The Taliban refused to reciprocate an extension to Ghani’s unilateral cease-fire and has conducted bloody attacks against government forces, drawing harsh criticism against Ghani for his move from his political rivals. Sayed Salahuddin, Washington Post, "Fresh violence kills over 15 in Afghanistan as Islamic scholars debate Taliban war," 10 July 2018 So Mrs Merkel managed both to resolve the dispute and to avoid unilateral German action. The Economist, "Angela Merkel’s flawed deal on migrants," 5 July 2018 Last month, Kabul extended a unilateral ceasefire to mark the end of the Muslim holy month of Ramadan, hoping that the truce might encourage the insurgents to join a dialogue. Laignee Barron, Time, "Mike Pompeo Pushes for Peace Talks With the Taliban During a Surprise Stop in Afghanistan," 10 July 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'unilateral.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of unilateral

1802, in the meaning defined at sense 1a

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Last Updated

18 Sep 2018

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The first known use of unilateral was in 1802

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English Language Learners Definition of unilateral

: involving only one group or country


uni·lat·er·al | \ ˌyü-ni-ˈlat-ə-rəl, -ˈla-trəl \

Medical Definition of unilateral 

: occurring on, performed on, or affecting one side of the body or one of its parts unilateral exophthalmos

Other words from unilateral

unilaterally \ \ adverb


uni·lat·er·al | \ ˌyü-nə-ˈla-tə-rəl \

Legal Definition of unilateral 

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

Other words from unilateral

unilaterally adverb

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More from Merriam-Webster on unilateral

Spanish Central: Translation of unilateral

Nglish: Translation of unilateral for Spanish Speakers

Britannica English: Translation of unilateral for Arabic Speakers

Comments on unilateral

What made you want to look up unilateral? Please tell us where you read or heard it (including the quote, if possible).


alleviating pain or harshness

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