The horizon (from Greek orizein, to limit) is the line that separates earth from sky. More precisely, it is the line that divides all of the directions you can possibly look into two categories: those which intersect the Earth, and those which do not. At many locations, the true horizon is obscured by trees, buildings, mountains and so forth. The resulting intersection of earth and sky is instead known as the visible horizon...oh, wait...you meant the game...next time specify what you're refering to.
