Where does “trzebno” come from?

trzebno (Polish) comes from Polish trzeba, from Old Polish trzeba, from Proto-Slavic terba, from Proto-Germanic þerb-.

Ancestry of “trzebno”, step by step

StepLanguageWordMeaning
1Polishtrzebaexpresses the goodness of the following verb; it is needed, one ought to
2Old Polishtrzebait is needed
3Proto-Slavicterbaneed
4Proto-Germanicþerb-—
Every word from Proto-Germanic þerb- →Every word from Proto-Slavic terba →Every word from Old Polish trzeba →