Some of the dictionaries available under the category "Advanced Learner's Dictionaries":
Longman Dictionary of Contemporary English, 5th EditionCambridge Advanced Learner's Dictionary, 3rd EditionCollins Cobuild Advanced Learner's DictionaryOxford Advanced Learner's Dictionary, 8th editionMacmillan American English DictionaryMerriam-Webster's Advanced Learner's DictionaryOxford Word FinderOxford Dictionary of English

Longman Dictionary of Contemporary English, 5th Edition






Cambridge Advanced Learner's Dictionary, 3rd Edition




Collins Cobuild Advanced Learner's Dictionary


Oxford Advanced Learner's Dictionary, 8th edition



Macmillan English Dictionary and Thesaurus


Merriam-Webster's Advanced Learner's Dictionary



Oxford Dictionary of English