Ownership is a relationship between two entities that exists within the scope of control of a jurisdiction, in which one of them (called the owner) has legal, rightful or natural rights and/or duties to enjoy, dispose of, and control the other (called the owned).
The titles are specified by (the rules of) the legal system of the jurisdiction, and the meaning of an ownership instance (i.e.: what you can(not) do with it) depend on the ways in which such rules are enforced, and disputes resolved. Obviously both the owner and the owned must be known (i.e.: be legal entities) in that jurisdiction).
We may use adjectives in combination with 'ownership' to signify the kind of jurisdiction within which that relationship exists. For example, 'legal ownership' signifies that the relationship exists in a legal jurisdiction, and 'natural ownership' that it is in the jurisdiction called 'nature'. An example of natural ownership is any statement uttered or authored by (or on behalf of) a party (the owner of the statement), because parties have a natural right to express themselves.
Ownership is a means by which jurisdictions ensure that owners can autonomously enjoy, dispose of and control the entities that they owns to the extent of the entitlements (rights and duties) as defined in the jurisdiction's legal system, and within its scope of control.
Ownership is a relationship between two legal entities (called the owner and the owned) within a single jurisdiction, whose legal system (a) defines the rights and duties of the owner to enjoy, dispose of and control the owned, (b) enforces them, and (c) provides a means to settle disputes.
Ownership only has meaning within a jurisdiction that defines and enforces a set of rights and duties of the owner and/or the owned. The value of ownership is typically proportional to the extent in which the jurisdiction enforces such rights and duties.
Owning something does not imply possessing it (and vice versa). For example, if you find a coin that doesn't belong to you, you possess it but do not owns it. Also, its rightful owner obviously owns it, but doesn't possess it at that point in time. Still, a jurisdiction may have rules that create or dissolve ownership relationships depending on who possesses the entity.
While owners are typically parties, the model does not require this to be the case. Thus, if a jurisdiction decides that rivers own their respective banks, the model does not disapprove. But such rivers and their banks do need to qualify as legal-entities within said jurisdiction.
The model does not set limitations on the kinds of entities that can be owned, other than that they need to be known in the jurisdiction(s) that specify the rights and duties associated with ownership relationships.
In this framework, we say that a. an objective that a particular party pursues (i.e. towards which a party directs effort), is owned by that party, and the rights and duties associated with this ownership are defined by the jurisdiction that the party is itself. b. a risk that is associated with an objective is owned by the owner of that objective, and the rights and duties