Fast Dictionary Lookup in OS 10.4 Tiger

A cool feature I found in Tiger is the new Dictionary look up that is available as an application and a Dashboard widget.

You can popup the Dictionary by highlighting text in almost any application, Ctrl-clicking or right clicking your mouse button, and choosing Look Up in Dictionary from the popup menu.

You can also use the hot keys: hover over or highlight the word and press Ctrl-Command-D. The popup window will appear that defines the word and includes options to changeover between dictionary and thesaurus.
Here is a screenshot of it in action