The terms Noble family and Clans have the same meaning when referring to a group of ennobled Fae that are related through descent or marriage.
Only the original Founding families of the Light Fae are referred to with the "Clan" appellation:
Though the Kavanagh family is also a Noble Family, it is not called "Clan Kavanagh."
It is not known if the Dark Fae use a similar arrangement.