'archaism' originates from Greek, specifically the word 'arkhaismos,' where 'arkhaios' meant 'ancient.'

'arkhaismos' transformed into the Latin word 'archaismus,' and eventually became the modern English word 'archaism' through Middle English.

Initially, it meant 'ancient or old-fashioned,' but over time it evolved into its current meaning of 'a word or expression that is no longer in common use.'