I’ve been pondering recently about what the Apostle John  meant when he used the word world (Gr. kosmos) in his writings. I assume (reasonably) he’s using it consistently throughout his Gospel, his three Letters, and the Book of the Revelation. If I can count correctly (?!?), that’s 80 occurrences in his Gospel, 23 in his Letters, and 7 in Revelation.
He had a lot to say about the world, now that I see the results of that word count. Lots of those uses come from Jesus’ quotes (as John the Evangelist translates him from Aramaic), so I take it that John developed a usage and conception of the world drawn from his own emphasis on his Master’s teachings on the subject.
To get a little snarky for a moment, one thing I’m fully convinced John does not mean by world is what I suspect to be the popular interpretation, i.e. a meticulous headcount of every single human being. Here’s how it sounds in the Popular Evangelical Assumptive Translation’s mental rendering of probably the most famous use of world in the Apostle John’s work, i.e. Gospel of John 3:16:
For God really desperately passionately loved every single precise individual head-for-head in exactly the same way that he gave his one and only Son that whosoever!—yeah, anybody and everybody who wants to get in on this plan!—chooses to believe in him would not perish but have eternal life.
And just for fun, the Amplified Traditionalist Baptist Version reads like this:
For God really desperately passionately loved every single precise individual head-for-head in exactly the same way that he gave his one and only Son that who! so! ever!!—preach it y’all!! anybody and everybody who wants to get in on this plan by their glorious free will!—chooses to believe in him (and strolls down that aisle with every head bowed and every eye closed and prays that teary-eyed prayer with a deacon and gives his crisis-conversion testimony for good measure) would not perish (and will definitely stop drinking beer and smoking cigarettes) but have eternal life.
Um, it doesn’t say that (and it doesn’t mean that either). It says:
For in this manner God loved the world: he gave his unique Son so that all of the believing ones would not perish but have eternal life.
But I digress (as always) rather severely.
So the Word made the world, and the Word came into the world but was unknown to the world. And Jesus, the Word made flesh, is the light of the world as well as the bread from heaven who gives life to the world. And he’s the Lamb of God who takes away the sins of the world. And he’s the propitiation for the sins of the whole world.
And the whole world lies in the grip of the evil one. God loved the world, but we are not to love the world nor the things in the world. Friendship with the world is enmity with God. Jesus doesn’t pray for the world but for those whom the Father gave him out of the world.
And we have a this world and a that world. This world has been judged, and the ruler of this world has been cast out. Those who don’t believe in Jesus are of this world, but Jesus is not of this world. More so, Christ’s Kingdom is not of this world. Christ and his Kingdom are of that world.
So what is the semantic center for the usage of world in the Johannine corpus?
This world and that world are eschatological ages. The Kingdom is in the age to come, the Eschaton. The writer-preacher  of the Letter to the Hebrews uses world similarly and has the same thing in mind. Man wasn’t meant to rule over this world but the world to come (Hebrews 2:5). Christ is the new Man, the new Adam. He is of the new creation, the new heavens and new earth, the world to come.
Now, shall I go get myself some Not Of This World (NOTW) merch?
 Also called John the Evangelist, i.e. John the Gospel Writer. And let’s not forget to call him John the Presbyterian (Gr. presbyteros), i.e. John the Elder, so that we can differentiate Little John, Jesus’ youngest disciple from Cousin John, John the Baptist (Gr. baptistēs), i.e. “The Other John” aka John the Ceremonial Cleaner and Elijah Redux. :-p
 Apollos of Alexandria, an eloquent man, mighty in the Scriptures. :-p