A PDP is a 'planned descent point', also referred to sometimes as a TTS (time to see)point. Several airlines use the concept and it is discussed in the book Mental Math for Pilots. A VDP is published on approach plates and take obstacle clearance into consideration, PDPs are 'calculated' by the pilot to simulate a VDP. This gives the pilot a good reference point to start a descent that will result in a 'normal landing' (reference 91.175).
I discussed this in an earlier thread, I'll see if I can go back and find it.
Doc Holiday’s answer is probably what they are looking (especially if used in connection with VDP). It is also used in other aviation contexts: Power Distribution Panel (electrical system) and Pre-determined Point procedure used for fuel planning.