Subject
RSM uses Subject as a semantic role rather than an ontological superclass.
Specification-sourced: quoted from the governing specification, pending the applicable specification-owner approvals. The specification controls.
In RSMOne's words
Something becomes a Subject when an observation, claim, evaluation, activity or outcome is about it. Subjecthood says what an expression concerns, not what the thing fundamentally is; no universal Subject superclass is stored, and a watershed can be a Subject without ever acting.
What it is not
Subject ≠ Actor
A Subject is what an expression concerns; an Actor is the entity responsible for performing the action. 02 §3.2 · Subject Is Not Actor
Subject ≠ Participant
Being the Subject of an expression does not make an entity a Participant; participation is bound to a context such as a Formation or Activity. 02 §3.3 · Subject Is Not Participant