Plug in any word to Google Dictionary and not only will you get a Google's definition, you'll get the Wiktionary definition — the etymological history on Wikitionary is an interesting read, did you know "ginormous" was first coined in the 1970s? The real gem in Google's word search, however, is how it drills trough Google's news archives to show you real-world uses of the word in current quotes. In the case of "ginormous" it returned examples like Simon Cowell and Michael Dell using the term within the last three years.
Have an interesting tool for studying language? Let's hear about it in the comments.