A Vertex from Graph Theory is simply a more formal name for a Node#1.3.6.1.4.1.33097.1.0.12.0 often used in mathmatics. We avoid the term as we think the term Node#1.3.6.1.4.1.33097.1.0.12.0 (often depicted with circles) is much clearer.
The fundamental unit of a graph $G=(V, E)$, which is part of the set $V$.
https://en.wikipedia.org/wiki/Graph_theory
https://medium.com/basecs/a-gentle-introduction-to-graph-theory-77969829ead8