By mathematical definition, an octagon is an 8 sided 2-D shape. A stop sign, technically, is not 2-D, so it is not an octagon. A stop sign is 3-D, and has 10 faces. We could consider only the front face of a stop sign, which would be an octagon (now, we are ignoring the thickness of the sign, and it has 8 sides).Click to see full answer. Accordingly, what is the shape of a standard stop sign? octagonal Likewise, what shape is a stop sign UK? octagon shape Likewise, people ask, what shape is a stop sign a hexagon? Stop signs are eight-sided. That makes them octagons, not hexagons (six-sided). In the United States, there is a pattern to the way road signs are shaped.Why stop signs are octagons?The unique eight-sided shape of the sign allows drivers facing the back of the sign to identify that oncoming drivers have a stop sign and prevent confusion with other traffic signs. It was also chosen so that it could be identified easily at night since the original signs were not reflective.