'inconsistency' originates from Latin, specifically the word 'inconsistentia,' where 'in-' meant 'not' and 'consistentia' meant 'standing firm.'

'inconsistentia' transformed into the French word 'inconsistance,' and eventually became the modern English word 'inconsistency' through Middle English.

Initially, it meant 'not standing firm,' but over time it evolved into its current meaning of 'lacking harmony or agreement.'