Definition:

1. Something different, abnormal, irregular or not easily classified

2. deviation from the common rule

3. in natural science; is a persisting deviation in a physical quantity from its expected value, e.g., the systematic difference between a measurement and a trend or a model prediction

4. a person, thing or event that is far from normal

5. in astronomy, the angular distance of a planet or satellite from its last perihelion or perigee.

Etymology: Anomaly comes from 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. Homos in Greek means “the same.”

In a Sentence

Summer snow, while an anomaly, is not unknown.

With the rise of bank frauds, using data to detect anomalies in credit card transactions is common.