bilateral

American  

[bahy-lat-er-uhl] / baɪˈlæt ər əl /

adjective

1. pertaining to, involving, or affecting two or both sides, factions, parties, or the like.

   a bilateral agreement; bilateral sponsorship.

2. located on opposite sides of an axis; two-sided, especially when of equal size, value, etc.

3. Biology. pertaining to the right and left sides of a structure, plane, etc.

4. Chiefly Law. (of a contract) binding the parties to reciprocal obligations.

5. through both parents equally.

   bilateral affiliation.

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noun

1. Informal. a bilateral agreement, especially regarding international trade.

bilateral British  

/ baɪˈlætərəl /

adjective

1. having or involving two sides

2. affecting or undertaken by two parties; mutual

   a bilateral treaty

3. denoting or relating to bilateral symmetry

4. having identical sides or parts on each side of an axis; symmetrical

5. sociol relating to descent through both maternal and paternal lineage Compare unilateral

6. relating to an education that combines academic and technical courses

7. a bilateral meeting

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Other Word Forms

• bilateralism noun
• bilaterally adverb
• bilateralness noun

Etymology

Origin of bilateral

First recorded in 1765–75; bi- ¹ + lateral

Explanation

When something is bilateral it has two sides or it affects both sides of something. Discussions between two political parties are called bilateral because both sides get to share their views. Bilateral comes from Latin: bi means "two" and lateralis means "belonging to the side." Debates about issues can be described as bilateral — as long as people on both sides get to speak. However, bilateral can describe anything with two sides, like some of the organs in the body: the brain, heart and lungs all have two distinct sides.

Example Sentences

But Spain's Foreign Minister Jose Manuel Albares denounced the detention of Abu Keshek as "illegal", saying it would further stain deteriorating bilateral ties.

From Barron's • May 2, 2026

Takaichi, on her first visit to Vietnam since becoming prime minister in October, aims to deepen bilateral cooperation on energy security and supply chain resilience amid major disruptions stemming from the Middle East crisis.

From Barron's • May 2, 2026

Following the welcome ceremony, the king joined Trump in the Oval Office for a closed-door bilateral meeting.

From Los Angeles Times • Apr. 28, 2026

Charles is Britain’s best diplomatic card to play at a time when bilateral relations are at a generational low.

From The Wall Street Journal • Apr. 27, 2026

To those who are genuinely concerned, I push a button to say, “I have spastic bilateral quadriplegia, also known as cerebral palsy. It limits my body, but not my mind.”

From "Out of My Mind" by Sharon M. Draper

Related Words

• mutual
• reciprocal