An extensive bridge consisting, strictly of a series of arches of masonry, erected for the purpose of conducting a road or a railway a valley or a district of low level, or over existing channels of communication, where an embankment would be impracticable or inexpedient; more widely, any elevated roadway which artificial constructions of timber, iron, bricks, or stonework are established. [Century Dictionary]
But the word apparently was coined by English landscape gardener Humphry Repton (1752-1818) for an architectural feature, "a form of bridge adapted to the purposes of passing over, which may unite strength with grace, or use with beauty ...."via,路，duct,管道。引申词义高架桥。
该词的英语词源请访问找单词词源英文版：viaduct 词源，viaduct 含义。
via,路，duct,管道。引申词义高架桥。