# constrain

/kənˈstɹeɪn/ (US) · /kənstɹˈeɪn/ (UK)

Source: https://englishreference.com/word/constrain
Updated: 2026-08-27

## Senses

### 1. to restrict or limit

verb · CEFR C1 · Academic

to limit what someone can do or how something can grow.

For teachers: to restrict the scope or freedom of an action or process. Often used in passive constructions to describe external limitations.

- The small budget will constrain our ability to hire new staff this year.
- The research team felt constrained by the strict ethical guidelines, which prevented them from pursuing several promising avenues of inquiry.

Usage: Commonly used in the passive voice: 'to be constrained by'.

### 2. to force or compel

verb · CEFR C1 · Formal

to force someone to do something they might not want to do.

For teachers: to compel or oblige someone to follow a specific course of action through pressure or necessity.

- Financial problems constrained the family to sell their old home.
- Circumstances constrained the board of directors to issue a public apology before the full investigation was complete.

Usage: Often follows the pattern 'constrain someone to do something'.

### 3. to physically confine

verb · CEFR C2 · Technical · Formal

to hold something back or keep it inside narrow limits.

For teachers: to physically confine or keep something within close bounds.

- The gas is constrained within a small metal tank.
- The structural integrity of the bridge depends on how the steel cables constrain the movement of the central span during high winds.

## Examples

- The narrow hallway constrains the movement of the large furniture.
- The budget constraints of the project forced the team to cancel several planned upgrades to the software.
- In physics, the laws of thermodynamics constrain the maximum efficiency of any heat engine, regardless of the materials used in its construction.

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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.