"world object" is the new term you introduce. It is, admittedly, more common than "unum" and not new in the sense that its parts are familiar, but you're already defining a new term.
It is a bit odd, but I think I like it.
Also, world object could be the 'object' for the 'world', as opposed to the unum of an item in the world.
It is a bit odd, but I think I like it.
Also, world object could be the 'object' for the 'world', as opposed to the unum of an item in the world.