The Wikipedia Corpus

This corpus contains the full text of Wikipedia, and it contains 1.9 billion words in more than 4.4 million articles. But this corpus allows you to search Wikipedia in a much more powerful way than is possible with the standard interface. You can search by word, phrase, part of speech, and synonyms. You can also find collocates (nearby words), and see re-sortable concordance lines for any word or phrase.