Did you know that in OS X Lion you can get a quick dictionary definition of any word with a simple trackpad gesture? In the past, you would have to look up a definition in Spotlight or through a right click menu.
In Lion, a quick definition is as easy as a three-finger double tap on your trackpad. Just mouse over any word and perform the gesture; a nice little, translucent window should pop up with a definition. No more Google searches when you’re typing in a word processor!