Dictionary

by Jim
(New York, NY)

On Mac OS X 10.4 and later, when you are in a native (Cocoa) Mac app, hover your mouse over a word and press Ctrl-Cmd-D. You will get a Dictionary definition for that word. Then you can move to another word and that will definition will display instantly as well.

Dictionary does not need to be open. But it won’t work on an non-native applications, like Firefox.