| Subject | English | German |
| phys. | proper boundary-value problem | echtes Randwertproblem |
| phys. | proper value | charakteristischer Wert (e.g. of the matrix) |
| phys. | proper value | Eigenwert (e.g. of the matrix) |
| tech. | proper value | Eigenwert |
| phys. | proper value problem | Eigenwertproblem |