The World Order and the World System Theorists

How do you differentiate a world order from what marxist world systems, theorists and there are, as you note in your book, diverse and divergent sets of scholars here that world systems theorists have called the world system. How does, how is a world order compared to a world system, or are they synonymous? I think world system serists have done some of the best work in terms of pointing to the parts of global history weve forgotten about.