| Rank | Abbreviation | Meaning |
|---|
| ***** | PISD | Philadelphia Independent School District
| |
| **** | PISD | Psychotropic-Induced Sexual Dysfunction
| |
| **** | PISD | Post Infidelity Stress Disorder
| |
| *** | PISD | Ponder Independent School District
| |
| *** | PISD | Physician Integrated Services of Denver
| |
| ** | PISD | Protein Infrared Spectra Databank
| |
| * | PISD | Post-Irradiation Sudden Deafness
| |
| * | PISD | Presque Isle Sewer District
| |
| * | PISD | Plano Independent School District
| |
| * | PISD | Personnel Information Systems Division
| |
| * | PISD | Personnel Information Systems Development
| |
| * | PISD | Partnership for Integrity in Scientific Dis-semination
| |
| * | PISD | Pearland Independent School District
| |
| * | PISD | Palacios Independent School District
| |
| * | PISD | Plains Independent School District
| |
| * | PISD | Pearland Independant School District
| |
| * | PISD | Peri Infarct Spreading Depressions
| |
| * | PISD | Pettus Independent School District
| |
| * | PISD | Plainview Independent School District
| |
| * | PISD | Prosper Independent School District
| |
| * | PISD | Perennial and Intermittent Stream Diversion
| |
| * | PISD | Progreso Independent School District
| |
| * | PISD | Paris Independent School District
| |
| * | PISD | Paradise Independent School District
| |
| * | PISD | Pickton Independent School District
| |