'backway' originates from English, specifically the words 'back' and 'way', where 'back' came from Old English 'bæc' meaning 'the rear' and 'way' came from Old English 'weg' meaning 'a road or path'.

'back' (Old English 'bæc') and 'way' (Old English 'weg') were used separately in early English; the compound form (Middle English compounds such as 'bakway'/'bak-weg') eventually produced the modern English compound 'backway'.

Initially it meant 'a way at the back' (literally the rear path); over time it has retained that core sense while also gaining figurative uses meaning an indirect or unofficial route or method.