| PAC | P1-derived Artificial Chromosome | - | Computer Acronyms(common) |
| PAC | Polycyclic Aromatic Compound | - | Computer Acronyms(common) |
| PAC | Perturbed Angular Correlation | - | Computer Acronyms(common) |
| PAC | Photoacoustic Calorimetry | - | Computer Acronyms(common) |
| PAC | Polyaluminum Chloride | - | Computer Acronyms(common) |
| PAC | Powdered Activated Carbon | - | Computer Acronyms(common) |
| PAC | P1 Artificial Chromosome | - | Medical |
| PAC | Pressure Alpha Center | - | Organizations |
| PAC | Probe Aerodynamic Center | - | Organizations |
| PAC | Problem Action Center | - | Organizations |
| PAC | Pan Africanist Congress -Partial Solar Calibrator - Patriot Advanced Capabilities - Political Action Committee -Primary Auditory Cortex | - | Astronomy |
| PAC | Polar Atmospheric Chemistry | - | Business and Finance |
| PAC | Public Access Catalog. May be used interchangeably with the term OPAC; may also mean a catalog of library holdings which is not online
| - | Human Genome |
