A river of central Italy rising in the northern Apennines and flowing about 240 km (150 mi) to the Ligurian Sea. Flooding of the Arno in 1966 caused severe damage to art treasures in Florence.
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Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.