A conceptual medium is a an expressive medium that primarily serves to express abstract thoughts and ideas. It is analogous to the concept of an artistic medium (e.g., painting, poetry, violin, etc), but pertains to the expression of conceptual thought rather than artistic expression.
Examples of such media would be spoken argument, written prose text, programming languages, mathematical symbolic notation, geometrical diagrams, explanatory comics, conceptual network diagrams (a.k.a., mindmaps), interactive simulations, data visualizations, markup languages, and semantic web technologies.