| HIPPO | Habitat destruction, Invasive non-native species, Population growth, Pollution, and Overharvesting 
| Others |
| HIPPO | Hasty International Perversion Provision Organisation
| Others |
| HIPPO | Health Information Project Presentation Online
| Others |
| HIPPO | Help International Plant Protein Organisation
| Others |
| HIPPO | Herbivore Induced Plant Protection Odor
| Others |
| HIPPO | Herbivore Induced Plant Protection Odour
| Others |
| HiPPO | Highest Paid Person Opinion
| Others |
| HiPPO | Highest Paid Person's Opinion
| Others |
| HIPPO | Highlands and Islands Performance Participation Opportunity
| Others |
| HIPPO | Highly Individual Peak People Only
| Others |
| HIPPO | Hydraulic Invasive Plant Processing Operation
| Others |