# unilateral

/ˌjunəˈɫætɝəɫ/ (US) · /jˌuːnɪlˈætəɹəl/ (UK)

Source: https://englishreference.com/word/unilateral
Updated: 2026-08-08

## Senses

### 1. one-sided decision

adjective · CEFR C1 · Formal · Academic

describes a decision or action taken by one person or group without the agreement of others involved.

For teachers: performed by or affecting only one person, group, or country involved in a situation, without the agreement of another or others.

- The manager made a unilateral decision to change the office hours without asking the staff.
- The country faced international criticism after its unilateral withdrawal from the climate treaty, which many saw as a betrayal of global cooperation.

Usage: Commonly used in political, legal, and business contexts to describe actions taken without consultation.

Teaching tip: Learners should note the prefix 'uni-' (one) and compare it with 'bi-' (two) and 'multi-' (many) to understand the scope of the action.

### 2. legal obligation

adjective · CEFR C2 · Technical · Formal

in law, an agreement where only one person or side has a duty to do something.

For teachers: denoting a contract or agreement in which only one party makes an express promise or undertakes a performance without receiving a reciprocal promise.

- A reward poster is a unilateral contract because only the person offering the money has a duty to pay.
- The court ruled that the document constituted a unilateral obligation, as the defendant had promised payment without requiring any specific counter-performance.

Usage: Used specifically in contract law to distinguish from bilateral agreements where both parties exchange promises.

Teaching tip: This is a highly specialized legal sense; for general purposes, the 'one-sided decision' sense is much more frequent.

### 3. medical/physical

adjective · CEFR C1 · Technical

affecting only one side of the body or one organ.

For teachers: occurring on, being confined to, or affecting only one side of the body or one of a pair of organs.

- The patient complained of unilateral hearing loss in her left ear.
- The MRI scan confirmed a unilateral lesion on the right hemisphere of the brain, explaining the lack of motor control on the left side.

Usage: Usually precedes the noun it modifies, such as 'unilateral pain' or 'unilateral weakness'.

Teaching tip: In medical English, this is the standard way to say 'on one side' rather than using everyday language.

## Examples

- The company made a unilateral decision to cancel the bonuses.
- The country faced international criticism after its unilateral withdrawal from the climate treaty without consulting its regional partners.
- Legal scholars argued that the unilateral modification of the contract terms rendered the entire agreement voidable, as it bypassed the mandatory arbitration clause agreed upon by both parties.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.