Coined 1816 from Latin 'via' (road) + 'ductus' (led), modeled on 'aqueduct' — a road-leading structure.
A long bridge-like structure, typically consisting of a series of arches, carrying a road or railway across a valley or other low ground.
A modern English coinage modelled directly on 'aqueduct,' blending Latin 'via' (way, road, journey) and 'ductus' (a leading, a channel; past participle of 'dūcere,' to lead, to conduct). Latin 'via' derives from PIE *weǵʰ- (to carry, to go on a road), source also of English 'way,' 'wagon,' and 'convey.' Latin 'dūcere' (to lead) comes from PIE *dewk- (to pull
The word 'viaduct' was deliberately coined to parallel 'aqueduct' — if an aqueduct leads water (aqua + ductus), then a viaduct leads a way/road (via + ductus). This analogical word-formation happened during the canal and railway building boom of early nineteenth-century Britain, when engineers needed a term for elevated road bridges that were not carrying water.