'parallel' originates from Greek, specifically the word 'parallēlos', where 'para-' meant 'beside' and 'allēlōn' meant 'each other'.

'parallēlos' transformed into the Latin word 'parallelus', and eventually became the modern English word 'parallel' through Old French.

Initially, it meant 'beside one another', but over time it evolved into its current meaning of 'being similar or analogous'.