The German word "Stellschraube" means, in its technical sense (according to dict.cc):
- binding screw
- regulating screw
- set screw
- setting screw
- adjusting screw
However, in a metaphorical sense, it can also mean a "leverage point" to adjust something non-technical. For example, motivation might be a "Stellschraube" for teachers to create a fruitful learning atmosphere.
Is there an English word having a similar meaning?