outlier

American  

[out-lahy-er] / ˈaʊtˌlaɪ ər /

noun

outliers plural

1. something that lies outside the main body or group that it is a part of, such as a cow far from the rest of the herd, or a distant island belonging to a cluster of islands.

   The small factory was an outlier, and unproductive, so the corporation sold it off to private owners who were able to make it profitable.

2. someone who stands apart from other members of a group, such as by differing behavior, beliefs, or religious practices.

   There are a few scientists who are outliers in their views on climate change.

   Synonyms:

   outsider, heretic, iconoclast, dissenter, dissident, bohemian, eccentric, original, maverick, nonconformist

3. Statistics.

   1. an observation that is well outside of the expected range of values in a study or experiment, and which is often discarded from the data set.

      Experience with a variety of data-reduction problems has led to several strategies for dealing with outliers in data sets.

   2. a person whose abilities, achievements, etc., lie outside the range of statistical probability.

4. Geology. a part of a formation left detached through the removal of surrounding parts by erosion.

5. Obsolete. a person residing outside the place of their business, duty, etc.

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outlier British  

/ ˈaʊtˌlaɪə /

noun

1. an outcrop of rocks that is entirely surrounded by older rocks

2. a person, thing, or part situated away from a main or related body

3. a person who lives away from his place of work, duty, etc

4. statistics a point in a sample widely separated from the main cluster of points in the sample See scatter diagram

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Other Word Forms

Noun Inflected Forms

• outliers
  plural

Etymology

Origin of outlier

First recorded in 1600–10; out- + lier

Explanation

In statistics an outlier is a piece of data that is far from the rest; think of a graph with dots, where most dots are clustered together in the middle, but one dot, the outlier, is at the top. Think of an outlier as an outsider. An outlier refers to anything that strays from, or isn’t part of, the norm. If you like to sleep in a tent in the backyard while your neighbors and family sleep in their beds, you’re probably an outlier. You may also be an outlier if you have to travel far to your job. In geology, rock that is separated from another rock formation is called an outlier.

Example Sentences

Experts interviewed by AFP said Balogun's citizenship story is an outlier in the world of football, but that it nevertheless is an example of how migration is increasingly interwoven into the sport.

From Barron's • Jun. 18, 2026

Unlike the bands circling Seattle and Portland, Modest Mouse made a point of leaning into its outlier roots.

From Los Angeles Times • Jun. 9, 2026

"We will keep continuing to make these recommendations because Northern Ireland is an outlier," he said.

From BBC • Jun. 7, 2026

So what makes today such an outlier from the way that things usually work?

From The Wall Street Journal • May 24, 2026

The outlier, in the end, is not an outlier at all.

From "Outliers" by Malcolm Gladwell

Related Words

• aberration
• deviation
• eccentricity
• exception
• oddity