Props, shortened from the word "Properties" are objects used in acting. Often these objects will possess different attributes than that of the represented object from the fictional realm. This can include representations of magical objects, which naturally cannot possess magical properties, objects using different construction and materials for safety reasons, or objects made from different materials for reasons of weight or cost.
There is no single method of construction for props. The only criteria is that it conveys to the audience, the nature of the object being represented.