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

'anaisthētos' transformed into the French word 'anesthésique,' and eventually became the modern English word 'anesthetic' through Middle English.

Initially, it meant 'without sensation,' but over time it evolved into its current meaning of 'a substance that induces insensitivity to pain.'