



 
Robert, I had a couple of reactions  and therefore will respond a several levels: The usual starting point is plane, convex polygons (e.g. a square, a hexagon ...) In 3space, with a polyhedron (e.g. a cube) we have vertices, edges and faces. More generally, mathematicians use that word even in more abstract or unfamiliar situations. Hope this helps! Walter Whiteley
 


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