The world as an ordered system — the universe, the earth, humanity collectively, or the present world-system opposed to God. Kosmos originally meant 'order' or 'adornment' (hence 'cosmetic'). In the NT it carries a complex range: God loved the kosmos (John 3:16) yet believers are warned not to love it (1 John 2:15).
The tension around kosmos is intentional. God created the world and loves it, yet 'the whole world lies in the power of the evil one' (1 John 5:19). Christ came not to condemn the world but to save it (John 3:17), yet He says 'My kingdom is not of this world' (John 18:36). Believers live in the world but are not of it (John 17:14-16). The kosmos is simultaneously God's beloved creation and a system in rebellion.