'athanasia' originates from Ancient Greek, specifically the word 'athanasia', where the prefix 'a-' meant 'without' and 'thanatos' meant 'death'.

'athanasia' passed into Late Latin as 'athanasia' and then into Middle English, eventually becoming the modern English word 'athanasia'.

Initially, it meant 'without death' or 'immortality'; this basic sense has largely been preserved, though the term is now rare and chiefly literary or theological in use.