| Hydrogenase | hydrogenase |
| Dehydrogenase | dehydrogenase |
| Hydrogen | hydrogen |
| Hydrogenium | hydrogen |
| Hydroenergie | hydropower |
| Hydrosphäre | hydrosphere |
| Hydrolyse | hydrolysis |
| Iatrogenese | iatrogenesis |
| Gynogenese | gynogenesis |
| Phylogenese | phylogenesis phylogeny |
| Hydrochemie | hydrochemistry |
| Hydrodynamik | hydrodynamics |
| Hydrographie | hydrography |
| Hydrochorie | hydrochory |
| Hydrologe | hydrologist |
| Hydrologie | hydrology |
| Hydrometer | hydrometer |
| Hydronym | hydronym |
| Hydronymie | hydronymy |
| Hydrotherapie | hydrotherapy |