Periphery: the circumference, outside the boundary, the edge, the outskirts. 

If something is in your peripheral vision, you see it in the side of your line of view. 

From Greek περιφέρεια: moving around.  The Greek word comes from two smaller Greek words.  The preposition περί (peri) means, around.  The verb φέρω (phérō) means, I carry.