Legal right to the exclusive enjoyment of a thing. It can be asserted against the whole World.
Includes in particular the right to: (1) use a thing, (2) profit from a thing, and (3) dispose of or encumber a thing. Such right is always subject to the applicable law & social co-existence rules prohibiting causing harm to others.
Under specified conditions plots of land owned by the State Treasury or the local government (municipality) may be given to a perpetual usufructee with the right to use and collect profits, usually for the period of 99 years.
The rights of perpetual usufructee are nearly as wide as the owner's. He may for eg. sell his interest in the land or take out a mortgage against it.