bi·​lat·​er·​al | \(ˌ)bī-ˈla-t(ə-)rəl \

Definition of bilateral 

1 : affecting reciprocally two nations or parties a bilateral treaty a bilateral trade agreement

2 : having two sides dealing with a bilateral problem

3 biology

a : of, relating to, or affecting the right and left sides of the body or the right and left members of paired organs bilateral nephrectomy

b : having bilateral symmetry

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Other Words from bilateral

bilateralism \ (ˌ)bī-​ˈla-​t(ə-​)rə-​ˌli-​zəm \ noun
bilaterally adverb

Did You Know?

Since the prefix bi- means "two" in Latin, bilateral means essentially "two-sided". In the days when there were two superpowers, the U.S. and the Soviet Union regularly engaged in bilateral arms negotiations; such negotiations are much less common today. Sometimes bilateral refers to two sides of the same thing. A bilateral hip replacement, for instance, replaces both hip bones in the same operation. And bilateral symmetry (a term often used by biologists) refers to the fact that, in many organisms (such as humans), the left side is basically the mirror image of the right side.

Examples of bilateral in a Sentence

Recent Examples on the Web

The Kremlin and the White House are discussing a possible joint statement that Putin and Trump would issue at the summit with a plan for improving bilateral relations, Ushakov said. John Wagner,, "Trump and Putin will meet July 16 in Helsinki," 29 June 2018 Putin’s spokesman Dmitry Peskov said Tuesday that Bolton’s meetings in Moscow with Lavrov would focus on bilateral relations, international stability and regional problems. Kim Hjelmgaard And David M. Jackson, USA TODAY, "Report: Finland may host Trump-Putin for first formal summit," 27 June 2018 Taking the bilateral relations to a new level, the U.S. military recently renamed its Pacific Command as the U.S. Indo-Pacific Command. Vinay Kaura, Time, "Strategic Ties Between India and the U.S. Are Growing. But Russia Is a Stumbling Block," 11 June 2018 Much attention is thus focused on strengthening bilateral relations. The Economist, "Britain is increasingly willing to cosy up to nasty regimes," 17 May 2018 Describing himself as the spokesman for the United States there, Prado, who turns 71 in June, is helping smooth bilateral relations as the U.S. seeks to make the South American country more of an economic and political partner. Guillermo Contreras, San Antonio Express-News, "From Edgewood High School to American diplomacy," 28 May 2018 Niinistö will also hold bilateral meetings with both leaders Monday., "Trump arrives in Scotland for weekend at golf course," 13 July 2018 This year, according to Reuters, South Korea also paid about $857 million for the upkeep of U.S. troops under a 5-year bilateral cost sharing arrangement signed with the U.S. in 2014. Time, "Inside Camp Humphreys, South Korea: America's Largest Overseas Military Base," 13 July 2018 Letting the treaty lapse would send an ominous signal, because every other part of the bilateral arms-control regime left over from the cold war is either dead or crumbling. The Economist, "What Donald Trump and Vladimir Putin ought to talk about in Helsinki," 12 July 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'bilateral.' 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 bilateral

1751, in the meaning defined at sense 1

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Statistics for bilateral

Last Updated

9 Nov 2018

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The first known use of bilateral was in 1751

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English Language Learners Definition of bilateral

: involving two groups or countries


bi·​lat·​er·​al | \(ˈ)bī-ˈlat-ə-rəl, -ˈla-trəl \

Medical Definition of bilateral 

1 : of, relating to, or affecting the right and left sides of the body or the right and left members of paired organs bilateral nephrectomy bilateral tumors of the adrenal glands

2 : having bilateral symmetry

Other Words from bilateral

bilateralism \ -​ˌiz-​əm \ noun
bilaterality \ (ˈ)bī-​ˌlat-​ə-​ˈral-​ət-​ē, -​ˌla-​ˈtral-​ \ noun plural -ties
bilaterally \ (ˈ)bī-​ˈlat-​ə-​rə-​lē, -​ˈla-​trə-​lē \ adverb


bi·​lat·​er·​al | \ˌbī-ˈla-tə-rəl \

Legal Definition of bilateral 

: affecting, obligating, or shared by both parties

Other Words from bilateral

bilaterally \ -​rə-​lē \ adverb

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More from Merriam-Webster on bilateral

Spanish Central: Translation of bilateral

Nglish: Translation of bilateral for Spanish Speakers

Britannica English: Translation of bilateral for Arabic Speakers

Comments on bilateral

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


to clear from alleged fault or guilt

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