To my understanding the meaning changes a little between countries and for someone on International ops It would not be surprising to miss the subtle differences. In some countries, FAF is the final point on a Non-Precision Approach beyond which the Final Approach Segment is deemed to Commence. The previous post was correct in stating that the FAP, is the point on a Precission Approach at which the Final Approach segment is deemed to commence, and is usually the lowest level before which the final descent is initiated on the approach. The FAP and FAF are often coincident, howveer not always. Also, often the OM is coincident with the FAP, but not always, which in my experience has let to some confusion.
As far as HK is concerned, FAF and FAP mean the same thing, though FAF is used in reference to Precission and non precission approaches, and is the lowest level able to be assigned, or published prior to Final Decent on the Final Approach.
Happy to take any advance on this, hope it helps