bilateral

adjective

bi·​lat·​er·​al (ˌ)bī-ˈla-t(ə-)rəl 

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

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

Gupta was arrested and detained on June 30 in the Czech Republic through a bilateral extradition treaty between the U.S. and the Czech Republic. —Britney Nguyen, Forbes, 29 Nov. 2023

In early November, U.S. Special Presidential Envoy for Climate John Kerry and China’s Special Envoy for Climate Change Xie Zhenhua reached an agreement to revive a bilateral working group on environmental issues including advancing renewable sources of energy and reducing methane emissions. —Wang Jisi, Foreign Affairs, 23 Nov. 2023

However, the absence of both in utero (bilateral renal agenesis) impacts the development of the lungs. —Cara Lynn Shultz, Peoplemag, 27 Oct. 2023

Finland’s Foreign Ministry announced last month that the country of 5.6 million has concluded a deal on a new bilateral defense agreement with the United States. —Jari Tanner, The Christian Science Monitor, 17 Nov. 2023

As a deaf person who wears bilateral cochlear implants, the issue of accessibility has been close to her heart for a long time. —Michael Andor Brodeur, Washington Post, 17 Nov. 2023

The bears have long been the symbol of the U.S.-China friendship since Beijing gifted a pair of pandas to the National Zoo in Washington in 1972, ahead of the normalization of bilateral relations. —Didi Tang, Fortune, 16 Nov. 2023

Mark Kelly President Biden met Chinese President Xi Jinping on Wednesday in California, and the atmospherics suggested a new era of bilateral good feelings. —The Editorial Board, WSJ, 15 Nov. 2023

Breaking a yearlong silence between them, President Biden and Chinese President Xi Jinping met Wednesday in Silicon Valley and vowed to reduce tensions in the world’s most important bilateral relationship. —Courtney Subramanian, Los Angeles Times, 15 Nov. 2023

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Word History

First Known Use

1751, in the meaning defined at sense 1

Phrases Containing bilateral

• bilateral symmetry

• bilateral symmetry

Kids Definition

bilateral

adjective

bi·​lat·​er·​al (ˈ)bī-ˈlat-ə-rəl 

-ˈla-trəl

1

: having or involving two sides or parties

a bilateral treaty

2

: characterized by bilateral symmetry

bilaterally

-ē

adverb

Medical Definition

bilateral

adjective

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

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

-ˌiz-əm 

noun

bilaterality

(ˈ)bī-ˌlat-ə-ˈral-ət-ē, -ˌla-ˈtral- 

noun

plural bilateralities

bilaterally

(ˈ)bī-ˈlat-ə-rə-lē, -ˈla-trə-lē 

adverb

Legal Definition

bilateral

adjective

bi·​lat·​er·​al ˌbī-ˈla-tə-rəl 

: affecting, obligating, or shared by both parties

bilaterally

-rə-lē

adverb