PO and Product Ownership

From whatever I have seen, the title of Product Owner does not have a universally accepted definition, and that is fine. Orgs have their own ways to position the title of PO which suits their culture. 

Some of the ways, Orgs describe PO as…

one who owns the backlog,
one who writes the User Stories,
one who is a domain expert,
one who gathers requirements,
one who is the market representative,
one who plans roadmaps,
one who manages stakeholders,
one who takes it to the next level,
one who answers queries from Dev team,
one who you-name-it.

I have written a bit longish version here about the qualities I like to see in a PO.

But in shortest form, I would say PO as someone responsible for C-to-C ( Concept to Cash ).

Or I-to-I ( Idea to Invoicing ), which is same as C-to-C.

It is obvious that the PO cannot do single-headedly all the things required for C-to-C.

That is why the organization suitably augments the PO by whatever help/skills s/he demands.

But the fact remains that the PO is responsible for C-to-C.

If someone cannot accept that responsibility, s/he is not yet ready to own the product.