Great families
Nero scoffed at Gabriel's comment, though he could not help but recall the Soren name. He might really have noble lineage, though he'd be considered a member of a branch at best considering the relation was from his mothers side.
His mind went over what he knew of great families real quick. Since Kolar did not have any kind of nobility, great families was just an informal term representing a family with many high level card masters. But it was only informal because it wasn't officially recognised, not because the list of great families wasn't comprehensive.
Another reason why many people, Nero included, assumed that the great families weren't officially recognised was because the army wanted power to stay centralised, and admitting that a few specific families had accumulated a large influence went against the image they tried to portray.