Longdo is multiple bilingual dictionary search and compilation service. It consists of English - Thai, Japanese - Thai, German - Thai, French - Thai dictionaries.

• Collaborative model: everybody can contribute
• Free: no fee should be charged for its basic
  word-lookup usage.
• Open contents: the collaboratively developed
  dictionaries contents should be publicly available under
  an open source license.
• Moderate quality: the dictionary contents is not
  targeted to have very high quality (linguistically) as
  expected in commercial products, although it must
  be useful enough to users.
• Up-to-date: the dictionary contents must be regularly
  revised. It should be easy to add new entries
  and update the existing ones.
• Support multiple foreign languages: it should
  have a framework for multiple-language support. In
  the initial phase, three foreign languages are targeted:
  English, Japanese, and German.

More information: Longdo Dictionary