aberration
ab-uh-RAY-shunnounMeaning a departure from what is normal or right, often a brief one
Memory hook AB-ERR: wander away into ERROR. The train that has arrived at eight o’clock sharp every day for ten years is two hours late today. That one late day is an aberration.
The team’s one loss was an aberration in an otherwise perfect season.
In context Her grades had been excellent for years, so her teachers saw the failed quiz as an aberration rather than a sign that something was wrong.
Similar deviation, exception, abnormality, departure
Opposite norm, standard
From Latin aberrare, “to wander away”: ab (away) + errare (to wander, stray).