metaDaF is described as 'Multisearch interface for german-spanish dictionaries' and is a Dictionary in the Education & Reference category. There are five alternatives to metaDaF, not only websites but also apps for a variety of platforms, including Android, iPhone, iPad and Apple Watch. The best alternative is Wiktionary, which is both free and Open Source. Other great sites and apps similar to metaDaF are Tatoeba (Free, Open Source), Linguee (Free), Lion (LEO dictionary) (Free Personal) and PONS (Freemium).
At its core, Tatoeba is a large database of example sentences translated into several languages. Search example sentences translated into many languages. Add and translate your own sentences. It's collaborative, open, free, and even addictive.
Lion allows you to send a query to the German-English, -French, -Spanish and -Italian LEO dictionaries (Chinese is currently not supported) with a click of your mouse from almost all MS Windows applications.