In aircraft design what is the Manufacturer's Datum Point (MDP)?

The MDP is a reference or starting point used in manufacturing new airframes. Like weight and balance or CG point of reference.

Let me know if I am on the correct track with this answer please. 

Thank you.

Are you sure that MPD is "Manufecturer's Datum Point"? Perhaps it refers  to the Maintenance "Planing Document", which is a document that is part of the airworthiness certification process.

It is a point on or about an aircraft (when it is being built) from which all measurements are taken.