unilateral

adjective

uni·​lat·​er·​al ˌyü-ni-ˈla-tə-rəl 

-ˈla-trəl

1

a

: done or undertaken by one person or party

b

: of, relating to, or affecting one side of a subject : one-sided

c

: constituting or relating to a contract or engagement by which an express obligation to do or forbear is imposed on only one party

2

a

: having parts arranged on one side

a unilateral raceme

b

: occurring on, performed on, or affecting one side of the body or one of its parts

unilateral exophthalmos

3

: unilineal

4

: having only one side

unilaterally adverb

Did you know?

The world is a smaller place than it used to be, and we get uncomfortable when a single nation adopts a policy of unilateralism—that is, acting independently with little regard for what the rest of the world thinks. A unilateral invasion of another country, for instance, usually looks like a grab for power and resources. But occasionally the world welcomes a unilateral action, as when the U.S. announced unilateral nuclear-arms reductions in the early 1990s. Previously, such reductions had only happened as part of bilateral ("two-sided") agreements with the old Soviet Union. Multilateral agreements, on issues such as climate change, often involve most of the world's nations.

Examples of unilateral in a Sentence

Our country is prepared to take unilateral action.

Recent Examples on the Web

Khamenei said several times in recent years that America's unilateral withdrawal from the nuclear deal is a proof that the U.S. can't be trusted and that there is no point in holding negotiations with America. —Barak Ravid, Axios, 28 Mar. 2025

And legal experts have noted that the unilateral transfer of the federal student loan system to another federal agency via executive action may violate federal law. —Adam S. Minsky, Forbes.com, 28 Mar. 2025

Musk, the face of the Department of Government Efficiency, has been behind unilateral efforts to gut federal agencies. —Barnini Chakraborty, The Washington Examiner, 28 Mar. 2025

Need to know India’s former commerce secretary says the country should resist unilateral concessions in U.S. trade negotiations. —Amala Balakrishner, CNBC, 27 Mar. 2025

Word History

First Known Use

1802, in the meaning defined at sense 1a

Rhymes for unilateral

• basolateral
• contralateral
• dorsolateral
• equilateral
• ipsilateral
• multilateral
• quadrilateral
• ventrolateral
• anterolateral
• posterolateral
• bilateral
• collateral

Kids Definition

unilateral

adjective

uni·​lat·​er·​al ˌyü-ni-ˈlat-ə-rəl 

-ˈla-trəl

: done or carried out by only one of two or more parties

unilateral disarmament

unilaterally

-ē

adverb

Medical Definition

unilateral

adjective

uni·​lat·​er·​al ˌyü-ni-ˈlat-ə-rəl, -ˈla-trəl 

: occurring on, performed on, or affecting one side of the body or one of its parts

unilateral exophthalmos

unilaterally

-ē 

adverb

Legal Definition

unilateral

adjective

uni·​lat·​er·​al ˌyü-nə-ˈla-tə-rəl 

1

: done or undertaken by one party

a unilateral mistake as to the terms

2

: of, relating to, or affecting one side of a subject

3

: containing a promise to perform made by only one party especially because the other has already performed (as by paying an amount)

an option contract is unilateral

unilaterally adverb