The River Arno in Florence.
Arno 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.
river in Tuscany, central Italy, flowing west into the Ligurian Sea: c. 150 mi (241 km)
Arno definition by American Heritage Dictionary
A river of central Italy rising in the northern Apennines and flowing about 241 km (150 mi) to the Ligurian Sea. Flooding of the Arno has caused severe damage to art treasures in Florence.