'non-' originates from Latin, specifically the word 'non', meaning 'not'. 'repeat' originates from Latin, specifically the word 'repetere', where 're-' meant 'again' and 'petere' meant 'to seek or go toward'.

'repeat' changed from Latin 'repetere' to Old French 'repetir' and then into Middle English forms (e.g. 'repeiten'/'repen') and eventually became the modern English word 'repeat'. The compound 'nonrepeating' is formed by adding the prefix 'non-' to the present participle 'repeating'.

Initially, Latin 'repetere' meant 'to seek or go after again'; over time it evolved into the sense 'to do or say again' in English. With the prefix 'non-' the meaning became 'not doing or occurring again', i.e. 'not repeating'.