Request for comments/Help for starting project terminologies

I agree with having Definitions, at least where needed for disambiguations; and of course, they would not hurt otherwise. I agree to start with English. I do not mind adding other languages as soon as an original glossary entry is stable, but we should carefully design a method to to expand glossary entries

• without confronting users with an endless list of all possible language translations,
• allowing users to view translations in selected languages in parallel,
• allowing several equivalent translations, or synonymes,
• allowing definitions or explanations to be translated, too, so as to support translators who understand less or no English.

My first idea to create a glossary had been to set up a namespace "Glossary:" with translateable pages holding the expressions, and probably /qqq pages holding explanations, but that seems not sufficient now.