bilateral

adjective

bi·​lat·​er·​al (ˌ)bī-ˈla-t(ə-)rəl How to pronounce bilateral (audio)
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
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
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.
The exchange was prepared following bilateral peace talks in Istanbul last week. Dragana Jovanovic, ABC News, 24 May 2025 For over a decade, the secular government’s bilateral diplomacy with the pope has been treated as separate from ecumenism efforts between the Russian Orthodox Church and the Holy See. Timothy Nerozzi, The Washington Examiner, 23 May 2025 Many bilateral and multilateral agreements have sprung up like mushrooms from these side conversations. Mary Nichols, The Conversation, 19 May 2025 Munn, 44, was diagnosed with bilateral breast cancer in April 2023. Vanessa Etienne, People.com, 19 May 2025 See All Example Sentences for bilateral

Word History

First Known Use

1751, in the meaning defined at sense 1

Time Traveler
The first known use of bilateral was in 1751

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Cite this Entry

“Bilateral.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/bilateral. Accessed 28 May. 2025.

Kids Definition

bilateral

adjective
bi·​lat·​er·​al (ˈ)bī-ˈlat-ə-rəl How to pronounce bilateral (audio)
-ˈla-trəl
1
: having or involving two sides or parties
a bilateral treaty
2
: characterized by bilateral symmetry
bilaterally
adverb

Medical Definition

bilateral

adjective
bi·​lat·​er·​al (ˈ)bī-ˈlat-ə-rəl, -ˈla-trəl How to pronounce bilateral (audio)
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
bilateralism noun
bilaterality noun
plural bilateralities

Legal Definition

bilateral

adjective
bi·​lat·​er·​al ˌbī-ˈla-tə-rəl How to pronounce bilateral (audio)
: affecting, obligating, or shared by both parties
bilaterally
-rə-lē
adverb

More from Merriam-Webster on bilateral

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