Source : WordNet®

cognomina
     See {cognomen}

cognomen
     n 1: a familiar name  for a person (often a shortened version of
          a person's given name); "Joe's mother would not use his
          nickname and always called him Joseph"; "Henry's
          nickname was Slim" [syn: {nickname}, {moniker}, {sobriquet},
           {soubriquet}]
     2: the name used to identify the members of a family (as
        distinguished from each member's given name) [syn: {surname},
         {family name}, {last name}]
     [also: {cognomina} (pl)]