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

Many allies, appearing surprised by the figure, have been asking whether existing bilateral aid being doled out would count toward the $100 billion commitment, or if this would be an entirely different commitment. —John Hudson, Washington Post, 4 Apr. 2024

Under the terms of the bilateral memorandum of understanding, the countries will jointly develop tests and perform at least one testing exercise on a publicly accessible model. —David Meyer, Fortune, 2 Apr. 2024

In light of this, analysts in Pakistan have questioned the wisdom of Mr. Dar’s comments on restoring bilateral trade. —Hasan Ali, The Christian Science Monitor, 1 Apr. 2024

This kind of alternating bilateral stimulation is thought to be the basis for eye-movement-desensitization therapy, one of the more effective treatments for P.T.S.D. —Ayelet Waldman, The New Yorker, 30 Mar. 2024

Founders should look at early customers as more than early traction, and invest in building bilateral feedback loops beyond routine account management. —John Jarosz, Forbes, 29 Mar. 2024

Japan’s prime minister, Fumio Kishida, then traveled to Seoul for a bilateral meeting, the first such visit in 12 years. —John Yoon, New York Times, 19 Mar. 2024

The deal is valid from May 1, 2024 through April 30, 2031, encompassing India’s tours of New Zealand in the 2026-27 and 2030-31 summers, as well as all other bilateral Tests, ODIs, and T20Is played in New Zealand during the period. —Naman Ramachandran, Variety, 27 Mar. 2024

Images and videos of war proliferate on the app, as do posts exhorting people to punish Mr. Biden’s support for Israel by not voting for him in 2024, paying little regard to his administration’s push for a bilateral cease-fire agreement and more aid into Gaza. —Anjali Huynh, New York Times, 26 Mar. 2024

Word History

First Known Use

1751, in the meaning defined at sense 1

Phrases Containing bilateral

• 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