anomaly
anom·a·ly
/əˈnɑːməli/ noun , pl -lies [ count ]
somewhat formal : something that is unusual or unexpected : something anomalous
A storm like that is an anomaly for this area. [=a storm like that does not usually happen in this area]
We couldn't explain the anomalies in the test results.
The doctor detected an anomaly [=irregularity] in my heartbeat.
