| Subject | English | German |
| piez., obs. | coupling factor for dielectric filters | Kopplungskoeffizient eines dielektrischen Filters |
| piez. | coupling factor for dielectric filters | Kopplungsfaktor eines dielektrischen Filters |
| earth.sc., life.sc. | filter factor | Verlängerungsfaktor |
| tech. | filter factor | Filterfaktor |
| opt. | filter factor | Verlängerungsfaktor (it is the degree to which the filter affects the photographic exposure) |
| opt. | filter factor | Filterfaktor (the degree to which the filter affects the photographic exposure) |