Vlastelin

Vlastelin pl. vlastelini) is the Bosnian (Serbo-Croatian word for the "magnate", derived from vlast ("rule, power, authority, government, management, office"). Other words are velmoža and velikaš, sometimes used interchangeably, particularly to designate regional lords. Vlastelin was used when referring to the highest and most powerful nobility in medieval Bosnia. Also, in Serbia and Croatia of the era, the velikaš and velmoža were most likely terms used in place of vlastelin. From vlastelin the term vlasteličić was derived for lower or lesser vlastelin status.[1]

In Eastern Europe the equivalent term would be boyar.

Titles used by the higher nobility in medieval Bosnia include Grand duke (person in command of military) in Bosnia specifically Grand Duke of Bosnia, Knyaz, Duke, Prince, etc.