| Acronym | Definition |
|---|
| PIIN➣Phase-Induced Intensity Noise |
| PIIN➣Procurement Instrument Identification Number |
| PIIN➣Pittsburgh Interfaith Impact Network (Pittsburgh, PA) |
| PIIN➣Procurement Item Identification Number |
| PIIN➣Police Integrated Information Network (Philadelphia, Pennsylvania) |
| PIIN➣Procurement Instrument/Instruction Identification Number |