Pax Means peace, a treaty that settles a kingdom would be a Pax.
A treaty between The Gods to settle a system within a battle forged Ethereal Brass Orb would be a Great Pax.
But a treaty that Settled the Laws of the Flow of Mana (Ethereal, Astral, Heroic, Fantastic, Technic, and Psionic, among the major), is called MetaPax.
Oddly there are several versions, and the contention among the powers to switch areas to another pax. takes place more often than actual war between gods. many Great and Planetary Paxes have more to do with the limits this competition takes place within than actual peace.