Highlight the word, click on the bookmarklet link, and it's automatically defined for you by dictionary.com. According to the author, "As I browse the web I often come across new terms or words that I do not fully understand. With the web, you are only a few clicks away from a dictionary. We created three bookmarklets that make it even easier to lookup any word that you select in your document" (For more information about other handy bookmarklets, search Sjhell City--we'ge got some great ones).....(free).....