Instant Dictionary in Safari: Control-Command-D
Here’s a very useful key combination that I had long forgotten about. If you’re in Safari (and many other Mac OS X apps), hit control-command-D while you hover over a word, a dictionary will pop up with that words definition! Very useful if you’re reading something and want to clarify the meaning of a word, spell checking, and whatever else you might need a dictionary for. Students and educators in particular should find this extra useful.
If you’d prefer to see the Thesaurus pop up instead, simply go into Dictionary.app’s preferences and switch the Thesaurus to be on top of Dictionary, like the picture shows.