'anesthesia' originates from Greek, specifically the word 'anaisthēsia,' where 'an-' meant 'without' and 'aisthēsis' meant 'sensation.'

'anaisthēsia' transformed into the Latin word 'anaesthesia,' and eventually became the modern English word 'anesthesia' through Middle English.

Initially, it meant 'lack of sensation,' and this meaning has largely remained the same in modern usage.