Where does “изба” come from?

изба (Macedonian) comes from Proto-Slavic jьstъba, from Proto-Germanic *stubu.

Ancestry of “изба”, step by step

StepLanguageWordMeaning
1Proto-Slavicjьstъbaroom
2Proto-Germanic*stubu—
Every word from Proto-Germanic *stubu →Every word from Proto-Slavic jьstъba →
изба — Etymology, Origin & Word History | Etymology Explorer