| Acronym | Definition |
|---|
| PAST | Pioneer America Society Transactions (publications) |
| PAST | Physical Ability and Stamina Test |
| PAST | Projection Approximation Subspace Tracking |
| PAST | Phased Array Systems and Technology (Conference) |
| PAST | Progressively Adaptive Sub-Tree |
| PAST | Association to Preserve African American Society, History, and Tradition, Inc |
| PAST | Paleo-Anthropology Scientific Trust (South Africa) |
| PAST | Parakeet Autism Syndrome |
| PAST | Professeur Associé à Service Temporaire (French: Associate Professor Temporary Duty) |
| PAST | Perturbation Approximate Sensitivity Technique |
| PAST | Pilot Activated Self Test (avionics) |