an ancient region in W Europe, including the modern areas of N Italy, France, Belgium, and the S Netherlands: consisted of two main divisions, one part S of the Alps (Cisalpine Gaul) and another part N of the Alps (Transalpine Gaul)
a river in N Italy flowing E into the Adriatic. 15 miles (24 km) long: in crossing this ancient boundary between Cisalpine Gaul and Italy, to march against Pompey in 49 b.c., Julius Caesar made a major military commitment.
