Plane of the representation of reality, considered separately to make it easier to study
Introduction to the notion
Merise identifies the separation of concerns: design, organizational, logical and physical.
Praxeme favors the term “aspect” which carries a similar, but slightly different, notion. In particular, “aspect” eliminates the hierarchical connotation that comes with the term “level.”
See the entry “Aspect” in the Thesaurus.