Fürst (German pronunciation: [ˈfʏʁst], female form Fürstin, plural Fürsten; from Old High German furisto, "the first", a translation of the Latin princeps) is a German word for a ruler and is also a princely title. Fürsten were, since the Middle Ages, members of the highest nobility who ruled over states of the Holy Roman Empire and later its former territories, below the ruling Kaiser (emperor) or König (king).
A Prince of the Holy Roman Empire was the reigning sovereign ruler of an Imperial State that held imperial immediacy in the boundaries of the Holy Roman Empire. The territory ruled is referred to in German as a Fürstentum (principality), the family dynasty referred to as a Fürstenhaus (princely house), and the (non-reigning) descendants of a Fürst are titled and referred to in German as Prinz (prince) or Prinzessin (princess).
The English language uses the term prince for both concepts. Latin-based languages (French, Italian, Romanian, Spanish, Portuguese) also employ a single term, whereas Dutch as well as the Scandinavian and Slavic languages (Russian, Polish, Ukrainian, Serbo-Croatian, etc.) use separate terms similar to those used in German (see knyaz for the latter).