P-code is an abbreviated term for Place Code.
Data standards such as geo/place-codes (P-codes) are essential to International humanitarian response data management in case of disasters. For the various humanitarian organizations, it provides the systematic means of linking and exchanging data through the agreement on a single standard list of reference codes for specific locations.  See Implementing P-Codes.
P-codes resolve the basic issue of what we all call a place. Using place-names as identifiers can easily lead to confusion over spelling, different languages or scripts as well as duplication.
P-codes are similar to zip codes and postal codes and are part of a data management system that provides unique reference codes to individual locations. These codes provide a systematic means of linking and exchanging data and analyzing relationships between them. Any information that is linked to one location with a p-code can be linked and analyzed with any other.
More about Humanitarian Response Pcode implementation.
- pcode tag has been used for the Haiti Response in 2010
- unocha:pcode tag has been added to Guinea, Liberia and Sierra Leone nodes [place] for the 2014 United Nations Mission for Ebola Emergency Response (UNMEER).