root

In network graphs and DNS, the root refers to the top-level node or domain from which all other nodes or subdomains originate. It's the starting point or primary domain that anchors a structure. For example, in the PlatPhorm network graph, the root node represents the primary site connecting the network's subdomains and services.

“All subdomains of platphormnews.com branch from the root domain, making it the central node in the network graph.”