| Acronym | Definition |
|---|
| PFO | Patent Foramen Ovale (defect of the heart) |
| PFO | Principal Federal Official (US DHS) |
| PFO | Proxy Factory Object |
| PFO | Product Function Optimizer |
| PFO | Persistent Felony Offender (various states) |
| PFO | Pyrolysis Fuel Oil |
| PFO | Playing for Others (teen development program; Charlotte, NC) |
| PFO | Pittsburgh Field Office (Pennsylvania) |
| PFO | Pinedale Field Office (US DOI) |
| PFO | Persistent Foramen Ovale (cardiology) |
| PFO | Power Fail Output |
| PFO | Paphos, Cyprus - International (Airport Code) |
| PFO | Pissed Fell Over (UK medical slang for drunk patient) |
| PFO | Profit From Operations |
| PFO | Pyruvate:Ferredoxin Oxidoreductase |
| PFO | Perron-Frobenius Operator |
| PFO | Pinyon Flat Observatory (earthquake reporting station) |
| PFO | Property and Fiscal Office |
| PFO | Plutonium Finishing Operation |
| PFO | Pink Floyd Online (fan site) |
| PFO | Palustrine Forest (environmental science) |
| PFO | Please Frig Off (polite form, as in a PFO letter for a refused resume) |
| PFO | Paint Flag Offset (marking underground utilities) |
| PFO | Project Formulation Office (NASA) |