'aperiodic' originates from Greek via Modern Latin/Scientific formation: Greek elements 'a-' (privative) + 'periodos' (period, cycle), where 'a-' meant 'not' and 'periodos' meant 'a cycle or recurring interval'.

'aperiodic' was formed in scientific/technical usage by combining the Greek-derived privative 'a-' with 'periodic' (from Greek 'periodos' through Latin/French/English) and then the adverb 'aperiodically' was created by adding the adverbial suffix '-ally'.

Initially formed to mean 'not periodic' in scientific contexts (describing phenomena lacking regular cycles); it has retained this core meaning and is now used both in technical and general contexts to mean 'in an irregular or nonperiodic manner'.