Where does “stålbørste” come from?
stålbørste (Norwegian Bokmål) comes from Norwegian Bokmål børste, from German Bürste, from Middle High German bürste, from Old High German burst, from Proto-Germanic burstiz, from Proto-Germanic bʰurstís, from Proto-Indo-European bʰr̥s-tí-s, from Proto-Indo-European bʰers- — top, tip, point.
stålbørste (Norwegian Bokmål): a wire brush
Ancestry of “stålbørste”, step by step