# subset

/ˈsəbˌsɛt/ (US) · /sˈʌbsɛt/ (UK)

Source: https://englishreference.com/word/subset
Updated: 2026-06-20

## Senses

### 1. a smaller group

noun · CEFR B2

a group of things or people that are all part of a bigger group.

For teachers: a group of items or individuals that form a specific part of a larger collection or population.

- The survey focused on a small subset of the population living in rural areas.
- While the policy affects all employees, a specific subset of part-time staff will receive additional benefits under the new contract.

### 2. mathematical set

noun · CEFR B2 · Technical

a set where every member is also a member of another set.

For teachers: a set A such that every element of A is also an element of a set B.

- In math, the set of even numbers is a subset of all whole numbers.
- The proof requires us to demonstrate that set X is a proper subset of set Y, meaning it contains some but not all of Y's elements.

### 3. to extract a part

verb · CEFR C1 · Technical

to choose or take a smaller part from a larger group of data.

For teachers: to extract or isolate a specific portion of a larger dataset or digital resource.

- We need to subset the data to look only at customers who joined this year.
- The software allows users to subset the original font file, including only the characters necessary for the specific document to reduce file size.

Usage: The verb is transitive and requires a direct object, typically a dataset or file.

## Examples

- This data represents a small subset of the total population.
- The researchers focused on a subset of patients who had not responded to previous treatments.
- In mathematical set theory, a set is considered a subset of another if all its members are also members of the parent set, including the possibility that the two sets are identical.

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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.