I think the difference is when you are told
to build an outbuilding, and told what you will store in it. In the South, some slaves ran businesses for their masters, but they still didn't have ultimate control of what they built and ran. For the serfs, the land was communally allocated on a year-by-year basis under the aristocrats or under socialism, so to them both systems looked the same. Ownership is a problematic measure because under many systems, such as most of the third world, it can't even be accurately determined, with overlapping claims that depend more on exerting will or ignoring what the official paperwork says. In the developed West, ownership is usually clear and straightfoward. Elsewhere, not so much, and in many places everything is owned by whoever you are negotiating with if you are looking to buy, but always somebody else if you are trying to collect a debt.