DN (diamétre nominal or nominal size),

Definition of DN (diamétre nominal or nominal size):

1. Number that approximates bore diameter measured in millimeters, and is only loosely related to manufacturing dimensions. Defined in ISO 6708 as numerical designation of size common to all components, other than those designated by the outside diameters or the thread sizes (which are defined in ISO 7).

2. Dadra and Nagar Haveli.