From some material that I'm now editing:
The Greek word cosmos is often rendered "world" but that English translation results in a degree of ambiguity. What do we mean by the "world"? Is the world a section of humanity, the entire human race, the framework in which humans move and breathe? Or is there another possible referent for this expression? Cosmos may also denote the universe—the entirety of all there is. Both Pythagoras and Heraclitus use the signifier to convey this idea. In the present context, when talking about cosmological dualism, the Greek term refers to the universe. The expression "world" is not an invalid handling of cosmos, but it does produce a rather fuzzy representation of the expression. In any event, cosmological dualism is the philosophical view that asserts the world (universe) is fundamentally two things. It claims that there are two absolute metaphysical principles representative of this particular species of dualism.
See H. G. Liddell and R. Scott, Greek-English Lexicon, ninth edition with revised supplement (Oxford: Clarendon Press), 985.
See Acts 17:24ff.
Compare this link: https://books.google.com/books?id=_JbuQ2zA8eEC&pg=PA281&dq=gospel+of+john+use+cosmos+for+universe&hl=en&sa=X&ei=azqQVbr4EMSyggTIj7PABg&ved=0CCAQ6AEwAA#v=onepage&q=gospel%20of%20john%20use%20cosmos%20for%20universe&f=false
The discussion starts on p. 282.