Included in Leopard’s Dictionary and Thesaurus is now the ability to search the wikipedia online database and through Apple terminology. Here are some examples.
Version 10.5 now includes the ability to search the wikipedia online database or through a database of Apple terminology through the Dictionary application.
Here are some examples. This is only available when you are online.
Through Spotlight search for “Dictionary” to open the Dictionary and Thesaurus application.
After searching for a term, you can select the “Apple” or “Wikipedia” buttons to search those databases.
Any application that has access to the OS X dictionary will display this information as well. Here is an example out of iWork’s Pages…