Mac OS X 10.4 or later Leopard users can download a different version here.
ProVoc is a Mac application that helps you to use flashcards to learn vocabulary from different languages.
You can create your own lessons with the words that you think are most important, or you can use vocabulary created by other users.
To create your own list, you must enter every word in your native language, including your definitions and related words in your own language. Other options you can activate are: a descriptive image, difficulty level, translation in both languages, and more
you can download vocabulary packs organized by the application's website in different language lessons. There, you can subscribe to an RSS feed that will keep you updated with new packs and other news.