anomaly
noun
anom·a·ly
ə-ˈnä-mə-lē 
plural anomalies
1
: something different, abnormal, peculiar, or not easily classified : something anomalous
They regarded the test results as an anomaly.
2
: deviation from the common rule : irregularity
3
: the angular distance of a planet from its perihelion as seen from the sun
Did you know?
You might be familiar with the Greek word homos, which means "same." It is from this word that we get words like homonym, homogeneous, and homophone, all of which have to do with sameness or similarity. What does this have to do with anomaly? Although it's not obvious, homos is a part of the etymology of anomaly, too. Anomaly is a descendant of the Greek word anōmalos, which means "uneven" or "irregular." Anōmalos comes from the prefix a- (meaning "not") and the word homalos (meaning "even")—and homalos comes from homos.
Examples of anomaly in a Sentence
In approximately 10% of patients, autism can be explained by genetic syndromes and known chromosomal anomalies (most of which have recognizable features in addition to autism) …
—
Lauren A. Weiss et al., New England Journal of Medicine, 14 Feb. 2008
Eleven minutes may not sound like much when you're waiting for a table at your favorite restaurant, but in the course of centuries, eleven minutes and change become a formidable chunk of time. By the 1300s, those superfluous minutes had added up to hours, then days, then more than a week. The calendar was losing time, irrevocably, to the "real" year, slipping further and further behind in its measurement of the earth's orbit. Anomalies began to creep into what had been the certainties of life. The spring equinox—one of two moments in the year when day and night are of equal length all over the earth, and which occurs on or about March 21—began to fall on March 16, then 15, then 14.
—Michelle Stacey, Harper's, December 2006
Californians aren't the only ones vexed by rolling brownouts and other power-supply anomalies. Everyday power spikes, surges, sags, and line noise cause computers, stereo equipment, televisions, telephones, and other delicate electronic equipment to go psychotic or have complete nervous breakdowns.
—Fortune, 25 June 2001
This policy may well have made sense back when steroid use was an anomaly. Now that bulking up with chemical help seems to be more popular than ever, it's incumbent on baseball to take action.
—Steve Kettman, New York Times, 20 Aug. 2000
We couldn't explain the anomalies in the test results.
her C grade is an anomaly, as she's never made anything except A's and B's before
Lauren A. Weiss et al., New England Journal of Medicine, 14 Feb. 2008
Eleven minutes may not sound like much when you're waiting for a table at your favorite restaurant, but in the course of centuries, eleven minutes and change become a formidable chunk of time. By the 1300s, those superfluous minutes had added up to hours, then days, then more than a week. The calendar was losing time, irrevocably, to the "real" year, slipping further and further behind in its measurement of the earth's orbit. Anomalies began to creep into what had been the certainties of life. The spring equinox—one of two moments in the year when day and night are of equal length all over the earth, and which occurs on or about March 21—began to fall on March 16, then 15, then 14.
—Michelle Stacey, Harper's, December 2006
Californians aren't the only ones vexed by rolling brownouts and other power-supply anomalies. Everyday power spikes, surges, sags, and line noise cause computers, stereo equipment, televisions, telephones, and other delicate electronic equipment to go psychotic or have complete nervous breakdowns.
—Fortune, 25 June 2001
This policy may well have made sense back when steroid use was an anomaly. Now that bulking up with chemical help seems to be more popular than ever, it's incumbent on baseball to take action.
—Steve Kettman, New York Times, 20 Aug. 2000
We couldn't explain the anomalies in the test results.
her C grade is an anomaly, as she's never made anything except A's and B's before
Recent Examples on the Web
These scans can detect benign anomalies that trigger unnecessary follow-ups and patient anxiety.
—Sindhya Valloppillil, Forbes.com, 1 July 2025
Beyond that in-the-moment reaction, though, the anomaly was not acknowledged during the remainder of the test, which seemed to conclude as planned.
—Josh Dinner, Space.com, 27 June 2025
The Lawson family’s story, famous in pain research, was not an anomaly.
—Christian Wolf, Scientific American, 25 June 2025
The rare genetic anomaly that causes it was discovered just last year, and families that once felt alone with their questions are now finding answers and one another.
—The Washington Post, San Diego Union-Tribune, 24 June 2025
See All Example Sentences for anomaly
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Sindhya Valloppillil, Forbes.com, 1 July 2025
Beyond that in-the-moment reaction, though, the anomaly was not acknowledged during the remainder of the test, which seemed to conclude as planned.
—Josh Dinner, Space.com, 27 June 2025
The Lawson family’s story, famous in pain research, was not an anomaly.
—Christian Wolf, Scientific American, 25 June 2025
The rare genetic anomaly that causes it was discovered just last year, and families that once felt alone with their questions are now finding answers and one another.
—The Washington Post, San Diego Union-Tribune, 24 June 2025
See All Example Sentences for anomaly
Cite this Entry
“Anomaly.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/anomaly. Accessed 15 Jul. 2025.
Copy CitationKids Definition
anomaly
noun
anom·a·ly
ə-ˈnäm-ə-lē
plural anomalies
1
: an act or instance of not following the general rule or method
2
: something anomalous : something different, abnormal, strange, or not easily described
Medical Definition
anomaly
noun
anom·a·ly
ə-ˈnäm-ə-lē
plural anomalies
: a deviation from normal especially of a bodily part
the infants demonstrated congenital anomalies
personality anomalies
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