The New Oxford American Dictionary is the most accurate and richly descriptive picture of American English ever offered in any dictionary. Oxford's American editors drew on a 200-million-word databank of contemporary North American English, plus the unrivaled citation files of the world-renowned Oxford English Dictionary.
The WordWeb version contains the latest 2009 updates, with 500 new head words, making this the most comprehensive and up-to-date American English reference.
Features include:
200 000 distinct words, phrases and derived forms
68 000 audio pronunciations from the Oxford Sound Bank
76 000 usage examples
35 000 etymologies
Includes word list of over 200 000 entries for word finding and use with Crossword Compiler
The download size is about 120MB (you can also order a CD-ROM).