World From Top, By Klaus Lerdorf

World population is the sum of all human populations at any time; similarly, world economy is the sum of the economies of all societies (all countries), especially in the context of globalization. Terms like world championship, gross world product, world flags etc. also imply the sum or combination of all current-day sovereign states.
In terms such as world religion, world language and world war, world suggests international or intercontinental scope without necessarily implying participation of the entire world.
In terms such as world map and world climate, world is used in the sense detached from human culture or civilization, referring to the planet Earth physically.