Supreme System Lord
A title at times given to the most powerful of all Goa'uld System Lords. Though the System Lords are rivals they often gather in council to negotiate in their mutual self-interest, and when one of them becomes especially powerful they will defer to the Supreme System Lord to a degree -- always waiting for an opportunity to gain the upper hand.
For many years Ra was the Supreme System Lord. His death above Abydos disturbed the balance of power among the other Goa'uld. Some years later the powerful Anubis used his knowledge of Ancient technology to seize a place of prominence among the System Lords, but there is no indication he was ever awarded the title of "Supreme System Lord" in any formal way. And when Baal seized the armies and territory of a defeated Anubis for himself, the rest of the System Lords formed a United Alliance against him.
Hathor - The Tok'ra leader Garshaw identifies Ra as "the Supreme System Lord."