Mac OS 10.8 added a Chinese dictionary to the built-in Dictionary app. This is a Chinese-Chinese (simplified characters only) dictionary and so will not be very useful to beginning learners.
The dictionary has to be enabled before you can use it:
- Open the Dictionary app (in the Applications folder).
- From the menubar, select Dictionary > Preferences.
- Check the box next to 现代汉语规范词典.
While you’re in the Dictionary app preferences, you may want to enable a Chinese version of Wikipedia; both traditional and simplified are available. First check the box next to Wikipedia and then the language choices will appear.
If you are looking for a Chinese-English dictionary to add to the Dictionary app, there is 小词典 Xiao Cidian by Rob Rohan. 小词典 uses CC-CEDICT. Download the desktop version (free as of this writing) from the xiaocidian.com and follow the installation instructions on the website. Once installed, you can use it just like the Apple-supplied dictionaries. The website hasn’t been updated, but I have tested it in Mountain Lion and it seems to work fine still.
Now you will see results from all enabled dictionaries, as well as Wikipedia, when you look up a Chinese word in a compliant app (this include Safari, Mail, and other Apple apps; apps by other developers may not support Dictionary app look-ups).
To do a Dictionary app look-up, you can select a word/phrase and either
- right-click (two-finger tap) and choose “Look up …” from the contextual menu that appears. This brings up a small pop-up Dictionary window, without launching the Dictionary app, in Mountain Lion.
- use the shortcut command-option-shift-D (which can be customized on the Keyboard preferences). This launches the Dictionary app and opens a full window.
You can also search for words in the Dictionary app via Spotlight. Just type into the Spotlight search box. In Mountain Lion, the Spotlight results will include “Look Up” near the bottom of the list. When you select that, the Dictionary app will launch and display the results from all your enabled dictionaries.
OS X (Mountain Lion) is available from the Mac App Store.