Online Dictionary: Cambridge

There's a version of the Cambridge dictionary online. It's free, and in many situations it works better than Google Translator. The only problem is that it's monolingual (Enlish - English), so it requires more knowledge of the language. Because of that, beginners might have some problems using it. Apart from that, it's a great tool for students and teachers.

So, take a look: http://dictionary.cambridge.org/