'wean' originates from Old English, specifically the word 'wenian,' where 'wen-' meant 'to accustom or train.'

'wenian' transformed into the Middle English word 'wenen,' and eventually became the modern English word 'wean.'

Initially, it meant 'to accustom or train,' but over time it evolved into its current meaning of 'to detach from a source of dependence.'