Synonyms 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
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
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The agreement comes after Bangladesh signed an economic partnership agreement with Japan in February, its first bilateral free trade deal. Jasmin Malik Chua, Footwear News, 4 Aug. 2026 And the United States itself did not begin to seriously deliberate the terms on which the war might end—especially the scope of the bilateral security guarantees Washington might provide Ukraine—until 2024. Dafna H. Rand, Foreign Affairs, 4 Aug. 2026 The rare bilateral intervention in Japan’s currency market was designed to prop up the yen from its 40-year low against the dollar. John Liu, CNN Money, 3 Aug. 2026 Michigan relies on supply chains that are heavily integrated with Canada after decades of policies that encouraged reducing bilateral trade barriers. ABC News, 30 July 2026 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 5 Aug. 2026.

Kids Definition

bilateral

adjective
1
: having or involving two sides or parties
a bilateral treaty
2
: characterized by bilateral symmetry
bilaterally
adverb

Medical Definition

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

Legal Definition

bilateral

adjective
: affecting, obligating, or shared by both parties
bilaterally
-rə-lē
adverb

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