Where does “rotta” come from?

rotta (Old Norse) comes from Proto-Germanic ratō, from Proto-Germanic rattaz, from Proto-Indo-European Hreh₃d- — to scrape.

Ancestry of “rotta”, step by step

StepLanguageWordMeaning
1Proto-Germanicratō—
2Proto-Germanicrattazrat
3Proto-Indo-EuropeanHreh₃d-to scrape
Every word from Proto-Indo-European Hreh₃d- →Every word from Proto-Germanic rattaz →Every word from Proto-Germanic ratō →