The core idea of this root was:
It basically referred to long, thread like somewhat solid things.
In ancient Greece, the root became neuron and the Greeks used in among other things in the context of anatomy, few tendons and also for nerves, because they are a long chord as well.
That’s where the word nerv is from, and both neuron and nerv later focused entirely on … well… nerves.
There are no other members of this family that I could find.