'ascesis' originates from Greek, specifically the word 'askēsis' (ἀσκησις), where the root 'ask-' meant 'to exercise, train'.

'ascesis' passed into Late Latin/Medieval Latin as 'ascesis' or 'ascesis', then entered Middle English and eventually became the modern English word 'ascesis'.

Initially, it meant 'exercise' or 'training' (in a general sense), but over time it evolved to denote specifically 'spiritual or self-denying discipline' in modern usage.