PDI
- Diiminopyridine
- Ideal Democratic Party
- Independent Democratic Pole
- Indonesian Democratic Party
- Investigations Police of Chile
- Pacific Data Images
- Pacific Deterrence Initiative
- Party for Justice and Integration
- Paul Drude Institute
- Pentaho Data Integration
- Peripheral drift illusion
- Philippine Daily Inquirer
- Pilot direction indicator
- Polydispersity index
- Portable Database Image
- Postal Development Indicator
- Power distance
- Powered Descent Initiation
- Program and Debug Interface
- Protein dispersibility index
- Protein disulfide isomerase
- Versit Consortium