viaduct definition by Webster's New World
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio. Used by arrangement with John Wiley & Sons, Inc.
a long bridge consisting of a series of short spans supported on piers or towers, usually to carry a road or railroad over a valley, gorge, etc.
Origin: Classical Latin via (see via) plush (aque)duct
viaduct definition by American Heritage Dictionary
A series of spans or arches used to carry a road or railroad over a wide valley or over other roads or railroads.
Origin: Latin via, road; see via + (aque)duct.