The Corpus of Contemporary American English (COCA) is the largest freely-available corpus of English, and the only large and balanced corpus of American English. It is much more than a simple online dictionary. The corpus was created by Mark Davies of Brigham Young University, and it is used by tens of thousands of users every month (linguists, teachers, translators, and other researchers). COCA is also related to other large corpora that we have created.

The corpus contains more than 425 million words of text and is equally divided among spoken, fiction, popular magazines, newspapers, and academic texts. It includes 20 million words each year from 1990-2011 and the corpus is also updated once or twice a year (the most recent texts are from March 2011). Because of its design, it is perhaps the only corpus of English that is suitable for looking at current, ongoing changes in the language...

Discover more on http://corpus.byu.edu/coca/