outlier

American  

[out-lahy-er] / ˈaʊtˌlaɪ ər /

noun

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.

---

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

---

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

When he went back to one—which most pros consider to be the correct number of gloves—it went so poorly that Rai went back immediately to being a sartorial outlier.

From The Wall Street Journal • May 18, 2026

Florida’s history education program is not an outlier.

From Salon • May 14, 2026

QCi was a notable outlier, with its share price plunging 38%.

From Barron's • May 11, 2026

The final tornado was an outlier, showing up much farther south at around 6:30 p.m., in Terra Bella in Tulare County, said Alex Cooke, a meteorologist for the National Weather Service’s Hanford/San Joaquin Valley office.

From Los Angeles Times • Apr. 25, 2026

By and large, they have only confirmed Cahokia’s status as a statistical outlier.

From "1491" by Charles C. Mann

Related Words

• aberration
• deviation
• eccentricity
• exception
• oddity