PPN
- Bis(triphenylphosphine)iminium chloride
- Guillermo León Valencia Airport
- Nigerien Progressive Party-African Democratic Rally
- Pacific Patriot Network
- Parameterized post-Newtonian formalism
- Pedunculopontine nucleus
- Pingat Pangkuan Negara
- Pre-Pottery Neolithic
- Principal protected note
- Protoplanetary nebula