| Hydroenergie | hydropower |
| Hydrologie | hydrology |
| Hydronymie | hydronymy |
| Hydrochemie | hydrochemistry |
| Hydrogenase | hydrogenase |
| Hydrologin | hydrologist |
| Hydrochorie | hydrochory |
| Hydrologe | hydrologist |
| Hydrotherapie | hydrotherapy |
| Drogerie | drugstore druggist’s druggist’s shop |
| Bioenergie | bioenergy |
| Ökoenergie | green energy green power |
| Synergie | synergy |
| Hydrogen | hydrogen |
| Hydrographie | hydrography |
| Hydrosphäre | hydrosphere |
| hydrieren | hydrogenate |
| Hydroforming | hydroforming |
| Hydrogenium | hydrogen |
| Hydrolyse | hydrolysis |