HFO
| Acronym | Definition |
|---|---|
| HFO | Heavy Fuel Oil |
| HFO | Haas Factory Outlet (machine tool distributor; Twinsburg, OH) |
| HFO | High Frequency Oscillator |
| HFO | Hole Full of Oil (oil exploration slang) |
| HFO | Hydrofluoro-Olefin (refrigerant) |
| HFO | Health Force Ontario (Canada) |
| HFO | Honolulu Forecast Office (National Weather Service; Hawaii) |
| HFO | Heavy Furnace Oil |