# outlier

/ˈaʊtɫaɪɝ/ (US) · /ˈaʊtlˌaɪə/ (UK) · CEFR C1 · Noun

Source: https://englishreference.com/word/outlier
Updated: 2026-05-20

## Definition

a value or piece of data that is very different from the others in a group. In geology, it can also describe a rock or mineral that is found far from where it usually appears.

For teachers: a data point that significantly deviates from the rest of a sample or population. In a geological context, it refers to a rock or mineral occurrence that is chemically or geographically distinct from its surrounding area.

## Examples

- The number 100 is an outlier in this small data set.
- The researcher noticed that one of the test results was an outlier, suggesting a possible error in the measurement process.
- Geologists identified a granite outlier within a field of sedimentary rock, indicating a period of intense tectonic activity that had pushed the intrusive body to the surface.

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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.