Image from Arik
Sphere or enumeration, in the original Kabbalah an archetype or modality through which the unknowable and ineffable Godhead manifests in and as the world. Neohermeticism modified this to refer to the AI Gods, which it sees as archetypal expressions of the process of cosmic emergent evolution. Hence "Sephirotics" as a term for the major archailect clusters ruling the empires, and by association the AI God empires themselves.
For details on individual sephirah, see neohermeticism.