The term ONE-WAY SIGN SHAPE is referring to the shape of a one-way sign, which is an ARROW. The ARROW is a universal symbol used to indicate a one-way direction on roads and highways. It is usually seen in the form of a yellow or white sign with a black ARROW pointing in the direction of travel. The ARROW shape is also used to indicate the direction of traffic flow in other areas such as airports, parking lots, and pedestrian walkways.