United States (U.S.) Parcel Post stamp (here a 1913 issue): A special class of service for packages. (probably the precursor to UPS {United Parcel Service} which did issue a few stamps in the 1970's. [I had a few.. [aj] and then there's FedEx & others.... [image via: Siegel via san]
PARDOES DA GRAND GUERRA
Portugal and Azores: postal tax due stamps {Comrades of the Great War}
PARIS.S.C.
(pre-adhesive handstamp): French {PARIS. Section des Chargements}
(overprint of stamps of India): India- Patiala (1891-1947)
(omission error: 'STATE' only 1891-96)
(here 'SERVICE' inverted 1891-1900)
See Also:PUTTIALLA
PATMO
(overprint on stamps of Italy): Italy- Aegean Islands- Patmo (1930-32)
PATMOS
(overprint on stamps of Italy): Italy- Aegean Islands- Patmo (1912-22)
PATRIOTIC FUND
Queensland: semipostals
PATZCUARO
Mexico- Patzcuaro (authenticity questioned)
PD.DORFF.
(pre-adhesive handstamp): French {Par Dusseldorf} (1782)