"Carin" is another short form of "Katherine" or "Catherine" although here in Germany where I live "Karin" is preferred so my name mostly gets spelled wrong in the first place. It is funny to learn that this form is also used in English as by now I haven't heard nor met a person from an English speaking country that is called "Carin". Anyway, unlike "Katherine" which comes from Greek and means "the pure one", "Carin" means as much as "amable person" or "kind person".