The definition gets a bit blurry around software, just like the definition of "ownership" does.
Colloquially, "proprietary software" means closed-source. You can definitely put it in context where it means "copyright without license"; but outside that context, the colloquial meaning is enough.
Colloquially, "proprietary software" means closed-source. You can definitely put it in context where it means "copyright without license"; but outside that context, the colloquial meaning is enough.