In the novel A Fire Upon the Deep, what is the name of the universal hierarchy of intelligence?

In A Fire Upon the Deep, the universal hierarchy of intelligence is called the Zones of Thought. Vernor Vinge divides the Milky Way into four concentric regions in which physical laws place different limits on intelligence and technology.

From the galactic center outward, the zones are the Unthinking Depths, the Slow Zone, the Beyond, and the Transcend. The Unthinking Depths permit only minimal intelligence. Earth's region, the Slow Zone, supports biological intelligence but prevents faster-than-light travel and true sentient artificial intelligence.

The Beyond allows advanced artificial intelligence, faster-than-light travel, and faster-than-light communication. Its outermost region, the Transcend, is home to incomprehensibly powerful entities known as Powers. A civilization may reach this level after undergoing a technological singularity.

The Zones of Thought are not simply a ranking of smart species. They are a universe-scale setting in which changing physical rules determine what minds and machines can do. The novel leaves open whether the zones are natural or artificially created, adding a mystery behind its central scientific idea.