die Brennnessel

The core idea of this root was:

sewing, spinning, twirling threads together

It’s the origin of a number or words related to garment, like needle and the German nähen (to sew).

German source I am using (dwds.de) also mentions the root *ned- as a variation of this one. That root carried the idea of binding, connecting and it is the origin or words like net, node, noose and the verbs annex (bind to) and connect (bind together).