Pir
- Khan Jahan Lodi
- PIR (gene)
- Pacific Imperial Railroad
- Parrot intermediate representation
- Partners in Research
- Passive infrared sensor
- Peak information rate
- Performance Index Rating
- Philadelphia International Records
- Philosophy in Review
- Phoenix International Raceway
- Pier 1 Imports
- Pierre Regional Airport
- Pir (Sufism)
- Pir (Zoroastrianism)
- Pir (song)
- Pir Roshan
- Pir of the Britons
- Pir, Kerman
- Pir, Satu Mare
- Pirs (disambiguation)
- Pittsburgh Industrial Railroad
- Polyisocyanurate
- Portland International Raceway
- Pre-Islamic recent period
- Private information retrieval
- Prosopographia Imperii Romani
- Protein Information Resource
- Public Interest Registry
- United States Army