| Acronym | Meaning |
| PBDD | Polybrominated Dibenzodioxin(s) |
| PBDE | Polybrominated Diphenyl Ether |
| PBDF | Polybrominated Dibenzofuran(s) |
| PBFFF | Potential Barrier Field-flow Fractionation |
| PBG | Photonic Band Gap |
| PBII | Plasma-based Ion Implantation |
| PBIRG | Pharmaceutical Business Intelligence And Research Gro |
| PBIRG | Pharmaceutical Business Intelligence And Research Gro |
| PBIRG | Pharmaceutical Business Intelligence And Research Gro |
| PBIRG | Pharmaceutical Business Intelligence And Research Gro |
| PBL | Peripheral Blood Lymphocyte |
| PBL | Planet Boundary Layer (in Atmospheric Chemistry And Physics) |
| PBM | Peripheral Blood Monocyte |
| PBM | Photochem. Box Model |
| PBM | Probability-based Matching |
| PBM | Proton Beam Micromachining |
| PBMC | Peripheral Blood Mononuclear Cells |
| PBMS | Photon Burst Mass Spectrometry |
| PBMS | Particle Beam Mass Spectrometry |
| PBMS | Performance-based Measuring System |
| PBO | Polarized Born-Oppenheimer |
| PBP | Penicillin Binding Protein |
| PBP | Pheromone-binding Protein |
| PBPC | Peripheral Blood Progenitor Cell |
| PBPD | Physiologically Based Pharmacodynamic |
| PBPK | Physiologically Based Pharmacokinetic |
| PBR | Peripheral Benzodiazepine Receptor |
| PBS | Phosphate Buffered Saline |
| PBSC | Peripheral Blood Stem Cell |
| PBSS | Porous Bed Biomass Support System |
| PBT | Poly(butylene Terephthalate) |
| PBTK | Physiologically Based Toxicokinetics |
| PBX | Plastic Bonded Explosive |
| PBZN | Peroxybenzoyl Nitrate |
| PC | Personal Computer |
| PC-BOSS | Particle Concentrator-Brigham Young University Organic Sampling System |
| PC-TD-SCF | Perturbation-corrected Time-dependent SCF |
| PCA | Preliminary Consequence Analysis |
| PCA | Polar Cap Absorption |
| PCA | Principal Component Analysis |
| PCA | Procoagulant Activity |
| PCAD | Power Conditioning And Distribution (in Spacecraft) |
| PCB | Polychlorinated Biphenyl |
| PCB | Printed Circuit Boards |
| PCBN | Polycrystalline Cubic Boron Nitride |
| PCBP | Phosphocholine-binding Proteinpar |
| PCCI | Premixed Charge Compression Ignition |
| PCCS | Phase-corrected Coupled-states (approxn. For Scattering Calcns.) |
| PCD | Photoconductive Decay |
| PCD | Polycrystalline Diamond |