| Untergrund | bedrock (geol.) subfloor subgrade (constr., tech., geol.) subsoil substrate substratum base basis footing ground base coat (paint etc.) base material surface undercoat (paint etc.) underground |
| Untergrundbahn | subway underground underground railway |
| Hintergrund | background |
| Underground | underground |
| Unterstand | cabana refuge |
| untergehend | setting |
| Unterdruck | depression low pressure partial vacuum underpressure |
| Untergang | downfall sinking decline |
| Untergrenze | lower limit |
| Untergruppe | subgroup |
| Unterpfand | pledge |
| Wintergrün | wintergreen |
| Integrand | integrand |
| Unterbühne | mezzanine |
| Untergattung | subgenus |
| Unterkleid | slip |
| Unterordnung | hypotaxis |
| Unterton | subharmonic |
| Unterzug | girder |
| Untugend | vice |