Modification
2) In mineralogy and crystallography - different types of crystals of the same substance, which are formed as a result of polymorphism and politics. 3) in machine building - a subspecies of one model, which is characterized by essential details of the main decoration. For example, the equipment of engines of different designs or capacities of one series of cars, planes or steamers; cancellation in the arrangement of the car body, or the filling of the cabin of the aircraft.