'anesis' originates from Greek, specifically the word 'ánesis', where 'ana-' meant 'up' or 'back' and 'hienai' meant 'to send' or 'to let go', together conveying the sense of 'loosening' or 'relaxation'.

'ánesis' was adopted into New Latin as 'anesis', and eventually became the modern English medical term 'anesis'.

Initially, it meant 'a loosening or relaxation', but over time it evolved into its current medical meaning of 'a period of relief from symptoms or pain'.