GRC-20 depends on core concepts of: “Spaces for grouping information, Entities and Relations for representing individual pieces of data, and Types for adding structure to information.” ...

Vectors are data structures that can track relationships between different snippets of information, much like a graph. However, they often store different kinds of relationships.

So, calling knowledge encoded on top of a graph structure a "knowledge graph" sounds natural. And the people doing this, the data modelers, have been called knowledge engineers, or ontologists.