Simple idea:

don’t ask “what’s similar?”, ask “where do independent semantic dynamics coincide?”

There is no positive without a negative. And even less so the neutral concept if the former do not exist... that, for me, is coherence and semantic geometry. What I have called the geometry of the concept.

Instead of treating coherence as a distance metric, I treat it as a dynamic property: whether independent semantic propagations converge or drift over a shared structure.

I call the diagnostic mechanism semantic diffraction.

Implementation here:

https://github.com/sgarcia87/Semantic-Diffraction-in-Conceptual-Graphs