anomaly
noun
[ əˈnɒm(ə)li ]
• something that deviates from what is standard, normal, or expected.
• "there are a number of anomalies in the present system"
Similar:
oddity,
peculiarity,
abnormality,
irregularity,
inconsistency,
incongruity,
deviation,
aberration,
quirk,
freak,
exception,
departure,
divergence,
variation,
outlier,
edge case,
rarity,
eccentricity,
• the angular distance of a planet or satellite from its last perihelion or perigee.
Origin:
late 16th century: via Latin from Greek anōmalia, from anōmalos (see anomalous).