English:

Websters
Meriam Webster
Open-dictionary
the free dictionary
Word IQ
Acronyms finder
U.S. Gov't Abbreviations & Acronyms
Cliche finder
Units of Measurement

Italian:

De Mauro
Garzanti
Italicon
Sapere
modi di dire

Bilingual Materials:

Garzanti-Hazon
Oxford-Paravia
Ultralingua
Foreignword

Other Materials:

The American's guide to British
converter, small freeware for weights & measures

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