Meaning of ZERO IN

WordNet Dictionary
	Definition:		[v]  adjust (as by firing under test conditions) the zero of (a gun); "He zeroed in his rifle at 200 yards" [v]  direct onto a point or target, esp. by automatic navigational aids
	Synonyms:		home in, range in, zero
	See Also:		adjust, aim, direct, place, point, set, target