'abnormal' originates from Latin, specifically the word 'abnormis,' where 'ab-' meant 'away from' and 'norma' meant 'rule or pattern.'

'abnormis' transformed into the French word 'anormal,' and eventually became the modern English word 'abnormal' through Middle English.

Initially, it meant 'away from the rule or pattern,' but over time it evolved into its current meaning of 'deviating from what is normal or usual.'