Longman, Study Dictionary of American English with Online Access - Pearson Education

Longman dictionaries are compiled using the Longman Corpus Network – a huge database of 430 million words of spoken and written English – collected from both British and American English sources.

They are easy to use and easy to understand: they are written using a limited vocabulary of just 2000 words - the Longman Defining Vocabulary - ensuring that they all have clear and understandable definitions.