| Acronym | Meaning |
| PFPD | Pulsed-flame Photometer Detector |
| PFPE | Perfluorinated Polyether |
| PFR | Plug Flow Reactor |
| PFRAM | Polymeric Ferroelectric Random Access Memory |
| PFRP | Process To Further Reduce Pathogens |
| PFS | Planetary Fourier Spectrometry |
| PFT | Pulmonary Functional Test(s) |
| PFTNA | Pulsed Fast Thermal Neutron Analysis |
| PFU | Plaque-forming Units |
| PFWM | Parametric Four-wave Mixing |
| PFZ | Polar Frontal Zone |
| PGA | Prostaglandin A |
| PGAA | Prompt Gamma-ray Activation Analysis |
| PGDN | Propylene Glycol Dinitrate |
| PGE | Platinum Group Elements |
| PGE | Prostaglandin E |
| PGF | Pseudo Green Function |
| PGHS | Prostaglandin H Synthase |
| PGIP | Polygalacturonase-inhibiting Protein |
| PGM | Platinum-group Metals |
| PGM | Platinum-group Mineral(s) |
| PGNAA | Prompt Gamma Neutron Activation Analysis |
| PGNP | Prompt Gamma Neutron Probe |
| PGO | Phantom Group Orbital |
| PGP | Previous Glacial Period (glacial Maximum Of O18 Stage 6; Predates The LGM) |
| PGR | Plant Growth Regulator |
| PGS | Phosphosilicate Glass |
| PGSE | Pulsed Gradient Spin Echo |
| PGWDB | Pesticides In Ground Water Database |
| PHA | Process Hazard Analysis |
| PHANTOMM | Photo-activated Nonintrusive Tracking Of Molecular Motion |
| PHAS | Pollution Hazard Assessment System |
| PHBTD | (number)projected-hartree-bogolyubov Tamm-dancoff(quantum Method) |
| PHC | Photonic Crystal |
| PHC | Primary Hepatocellular Carcinoma |
| PHD | P-helicity Decoupling Scheme (p=momentum) |
| PHDD | Polyhalogenated Dibenzodioxin(s) |
| PHDF | Polyhalogenated Dibenzofuran(s) |
| PHE | Potentially Harmful Element |
| PHEMT | Pseudomorphic High Electron Mobility Transistor |
| PHENIX | Pioneering High Energy Nuclear Interaction EXperiment |
| PHF | Paired Helical Filament |
| PHF | Periodic Hartree-Fock |
| PHF | Perturbative Hartree-Fock |
| PHF | Projected Hartree Fock |
| PHF-OCE | Perturbative Hartree-Fock One-center Expansion |
| PHFS | Perturbative Hartree-Fock-Slater |
| PHH | Planar Halogenated Hydrocarbon |
| PHIP | Para-Hydrogen Induced Polarization |
| PHO | Pseudoharmonic Oscillator |