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.

Wow! That is helpful, even better than my beloved dictionary widget
If you ctrl click on a word in a text entry box, then go to the Spelling selection on the menu, you can actually have the Aqua dictionary check the spelling as you type and underline misspelled words.
[...] anyone?). If you’re wondering where the word list is coming from, it’s tied to your Mac OS X dictionary, which is also readily available via a keyboard [...]
Any one knows if is possible to add a translator mode to de apple dictionary. would be really helpful and fast to have and option on the apple dictionary to translate word.
this is sick! love it thanks