Where does “воробышек” come from?

воробышек (Russian) comes from Russian воробе́й, from Proto-Slavic *vorbьjь.

Ancestry of “воробышек”, step by step

StepLanguageWordMeaning
1Russianворобе́йsparrow
2Proto-Slavic*vorbьjь—
Every word from Proto-Slavic *vorbьjь →Every word from Russian воробе́й →
воробышек — Etymology, Origin & Word History | Etymology Explorer