Where does “Ящук” come from?

Ящук (Ukrainian) comes from Ukrainian ук.

Ancestry of “Ящук”, step by step

Ящук traces back through two separate lines of ancestry.

via Ukrainian ук

StepLanguageWordMeaning
1Ukrainianук

via Ukrainian Я́ків

StepLanguageWordMeaning
1UkrainianЯ́ків
Every word from Ukrainian ук
Ящук — Etymology, Origin & Word History | Etymology Explorer