Raška, Zahumlje, Zeta (Duklja), Bosnia etc. are regions. The map is however showing political influence of lords, thus their realms. Region of Bosnia is not as big as the kingdom was e.g. Kingdom of Bosnia consisted at its peak, of Zahumlje, Usori, Soli, parts of Raška, and of course the Bosnia basin. The King of Bosnia was at that time however also the king of all Serbs, by descent, but not every ruler wanted to acknowledge his supremacy.