Wiktionary

Wiktionary is a spin-off project from Wikipedia to create a complete dictionary and thesaurus in all languages. Wiktionary is GFDL'd naturally.

It was started on December 12 2002. It's currently running unmodified Wikipedia-software, which IMHO isn't up to the job. eg. Normal users cannot look up all articles that do not contain a specific translation (to get a list where you can contribute). This could easily be accomplished using full-text search capabilities of MySQL 4.X.

You can interwiki link to Wikitionary using wiktionary:

We'll be doing our translation effort in Wiktionary. We'll start that by compiling a wordlist that contains all imaginable product groups, products and other glossary that needs to be translated to all languages.