Nexus

The nexus is the heart of a protoss base. Unlike most other protoss buildings it can be warped in without a pylon. It constructs probes and serves as a processing center for minerals and vespene gas.

Psionic Matrix

 * Main article: Psionic matrix.''

Protoss structures and, to a lesser extent, units, draw their energy from a great psionic energy matrix that emanates from Aiur. While a nexus provides a link to this matrix, khaydarin crystal-based pylons are needed to actually tap into the energy required to provide psionic energy to new colonies.

StarCraft
The nexus serves as the hub of any protoss base.

Development
In the StarCraft beta, the stargate was originally known as the nexus.

StarCraft II
The nexus remains much the same in terms of cost, appearance and function in StarCraft II. The protoss core macromanagement ability has been moved here.