This is the WORLD’S BESTSELLING advanced learner's dictionary, recommended by learners of English and their teachers, and used by 30 MILLION PEOPLE. It has more words and more help with British and American English than any other advanced learner’s dictionary. It is the only advanced learner's dictionary to list the most important words you need to know in English; the Oxford 3000
The dictionary is based on the British National Corpus, the Oxford Corpus Collection and the Oxford Reading Programme for language research.