All the cool things your Mac can do:
"If you highlight at word in any cocoa app (like Safari) and hit Command-Control-D, a small window will appear with the dictionary definition and part of speech of that particular word."
(Via The Unofficial Apple Weblog (TUAW).)
Now thats cool! I've had some occasions where I've really missed having quick access to a dictionary (I removed the dashboard dictionary app for memory reasons). Not any more!
