| PIR | Para Infantry Regiment 
| Others |
| PIR | Parachute Infantry Regiment
| Others |
| PIR | Parents In Room
| Others |
| PIR | Parrot Intermediate Representation
| Others |
| PIR | Partners In Recovery
| Others |
| PIR | Partners In Research
| Others |
| PIR | Pass In Review
| Others |
| PIR | Passive Infra Red
| Others |
| PIR | Passive Infrared
| Others |
| PIR | Pastor in Residence
| Others |
| PIR | Patient Information Reconciliation
| Others |
| PIR | Payment Information Repository
| Others |
| PIR | Peak Information Rate
| Others |
| PIR | Periodic Inspection Report
| Others |
| PIR | Periodic Interest Rate
| Others |
| PIR | Phoenix International Raceway
| Others |
| PIR | Pierre, South Dakota USA
| Others |
| PIR | Pieuse Innovation De Registres
| Others |
| PIR | Pilar Airport
| Others |
| PIR | Pile Installation Recorder
| Others |
| PIR | Pittsburgh Industrial Railroad
| Others |
| PIR | Pittsburgh Industrial Railroad Incorporated
| Others |
| PIR | Plymouth International Raceway
| Others |
| PIR | Police Initial Recruitment
| Others |
| PIR | Police Initial Recruitment test
| Others |
| PIR | Polyisocyanurate And Is Rigid
| Others |
| PIR | Portland International Raceway
| Others |
| PIR | Post Implementation Review
| Others |
| PIR | Post Industrial Recycled
| Others |
| PIR | Post-Implementation Review
| Others |
| PIR | Pre-Insertion Resistor
| Others |
| PIR | Prepare Interact Reflect
| Others |
| PIR | Prescribed Investor Rate
| Others |
| PIR | Primary Image Record
| Others |
| PIR | Prime Interest Rate
| Others |
| PIR | Principal in Residence
| Others |
| PIR | Principia Internet Radio
| Others |
| PIR | Priority Information Report
| Others |
| PIR | Priority Information Requirement
| Others |
| PIR | Priority Intelligence Requirement
| Others |
| PIR | Priority Intelligence Requirements
| Others |
| PIR | Private Information Retrieval
| Others |
| PIR | Problem Identification Report
| Others |
| PIR | Processor Identification Register
| Others |
| PIR | Processor Information ROM (Read-Only Memory)
| Others |
| PIR | Product Information Request (Release)
| Others |
| PIR | Production Illustration Request
| Others |
| PIR | Professiional In Residence
| Others |
| PIR | Program Information Report
| Others |
| PIR | Project Implementation Review
| Others |
| PIR | Property Interest Report
| Others |
| PIR | Property Irregularity Report
| Others |
| PIR | Protein Information Resource
| Others |
| PIR | Protocol Independent Routing
| Others |
| PIR | Public Interest Registry
| Others |
| PIR | Pupil Instruction Related
| Others |