Property law has been deep on all the various aspects of ownership for millenia, so there's a big "bundle of rights" which any specific type of ownership may or may not have.
One test for "full ownership" is the contractual restrictions that come attached; i.e. whether the law is the only thing that limits what you can do with the thing, or whether there are some extra conditions (which are not that rare in e.g. real estate deals for as long as we have recorded history); that's generally considered ownership but a restricted one. On the other hand, if you aren't prohibited to do that thing but simply aren't capable of doing it, that would still be considered unrestricted ownership.
But something that is a key part of ownership - especially with respect to various "buying" of e.g. games - is the ability to transfer it to others. If you can't give or sell the thing you've purchased to someone else, that clearly indicates that you don't own it.