# constraint

/kənˈstɹeɪnt/ (US) · /kənstɹˈeɪnt/ (UK)

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

## Senses

### 1. a restriction

noun · CEFR B2

something that limits your freedom to do what you want.

For teachers: a limitation or restriction on one's actions or choices. Often used in the plural to describe external pressures.

- Financial constraints meant the family could not afford a holiday this year.
- The project was completed on time despite significant budgetary constraints and a shortage of skilled labour.

### 2. emotional control

noun · CEFR C1 · Formal

the act of hiding your true feelings or behaving in a very controlled way.

For teachers: the state of being checked or restricted in the expression of natural feelings or impulses.

- They spoke to each other with great constraint after their argument.
- The diplomat maintained an air of polite constraint, refusing to let his personal frustrations show during the tense negotiations.

### 3. math/optimization

noun · CEFR C1 · Technical

a condition or rule that a mathematical solution must follow.

For teachers: a condition that a solution to an optimization problem or a mathematical model must satisfy.

- The engineer added a weight constraint to the design software.
- In linear programming, the feasible region is defined by the intersection of all given constraints within the model.

### 4. computing/databases

noun · CEFR C1 · Technical

a rule in a computer system that keeps data correct and organized.

For teachers: a rule or restriction enforced on data in a database to maintain integrity and consistency.

- The database has a constraint that prevents two users from having the same ID.
- The developer implemented a foreign key constraint to ensure that every order was linked to a valid customer record.

## Examples

- Time is the biggest constraint on this project.
- The architect had to work within the constraint of a very narrow building site.
- Budgetary constraints often force research teams to prioritise immediate practical applications over long-term theoretical exploration, potentially stifling innovation in the process.

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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.