Pretty much all learners know that die Mutter is the German word for mother.
What most learners don’t know, at least if they’re not into skilled crafts, is that die Mutter is also the word for:
In the sense of the counterpart of a screw.
English also calls this the female screw and the counterpart is the male screw, and the origin of these names is exactly what you think it is.
In German, the word for screw is die Schraube and the two types were originally called die Vaterschraube and die Mutterschraube. But over time, the people shortened the pair to die Schraube and die Mutter.
There is one language difference between the two types of Mutter though – the plural.
For the actual Mutter, it is die Mütter. And for the screw-Mutter, it is die Muttern.