| HYDRA | Helping You Downtown Roam Around 
| Others |
| HYDRA | Hierarchical Yet Dynamic Reprogrammable Architecture
| Others |
| HYDRA | Hierarchical Yet Dynamically Reprogrammable Architecture
| Others |
| HYDRA | Howdy, You Dope-Rad Animal
| Others |
| HYDRA | Hyderabad Disaster Response and Assets Monitoring and Protection
| Others |
| HYDRA | Hydrogen yielding destructive ray armor
| Others |