Using the OS X Dictionary and Thesaurus

The purest of the pure OS X apps support a full suite of OS X services, including Apple's Dictionary and Thesaurus. This includes Nisus Writer Express and Safari,
but not, surprisingly, Camino [see update re: camino] and certainly not Firefox. A TUAW comment suggests changing the kb shortuct:

...The built in dictionary is a nice app that is often useful. With most of Apple's apps you can hover over any word and press Command ^ D to get the definiton instantly.

This, however, is an odd key combination and the info goes away as soon as you release the keys.

If you set it up with a toggle key, like F12, the mini-dictioanry will stay put until you hit the toggle key again.

You can also now move the mouse to any word(s) you wish for instant access to multiple definitions...

I use opt-F12, because F12 is the default for widgets and one day I may find one I really like. This nicely improves this feature. The dialog box has a drop down icon that lets you switch to Thesaurus mode, and when the app is up you can use preferences to change the thesaurus/dictionary priority.

Update 5/8/07: Why it doesn't work in Camino

I asked Camino's developers about this. It's not enough for an application to be Cocoa, to benefit from the dictionary and integrated spell-checking the application also has to make use of OS X text rendering controls. That's not feasible for Gecko. They are looking at enabling dictionary access through other means, but there's no version for that yet.