| Abbreviation | Definition |
|---|---|
| PN | Pressure Nominal |
| PNA | P-Nitro-Anilide |
| PNA | Positive/Negative Anomaly |
| PNG | Pipeline Natural Gas |
| pNP | p-NitroPhenol (C6H5NO3) |
| PNPA | PolyNucleotide Phosphorylase A |
| PNPB | P-NitroPhenyl Butryate |
| PNPB | PolyNucleotide Phosphorylase B |
| PNPC | P-NitroPhenyl esters of Caporate |
| PNPP | P-NitroPhenyl Phosphate |
| Po | Polonium |
| PO4 | Phosphate |
| POA | primary organic aerosol |
| POC | Polar Organic Contaminant |
| POC | Product(s) of combustion |
| POCE | Project Oriented Chemical Education |
| POCR | Pavlodar Oil and Chemistry Refinery |
| POD | Preferred Organic Digester |
| POM | Partial Oxidation of Methane |
| POM | Properties Of Matter |