The centre — the point a thing turns about, and the still place that makes the turning possible. Sanskrit, केन्द्रम्. A centre holds without owning: this house's hub, needed by none of the realms it gathers.
Sanskrit kendram (centre, focal point), from kendra — itself likely a loan from Greek kentron (a sharp point, the centre of a circle) carried into Sanskrit through Hellenistic astronomical contact; the point a thing turns about, and the still place that makes the turning possible.
The hub realm, where every Resonance app in the house is found, opened, and kept current while each stands on its own — proven in code by the fact that no realm imports it back.