Where does “Теребейчук” come from?

Теребейчук (Ukrainian) comes from Ukrainian -у́к, from Proto-Slavic *-ukъ.

Ancestry of “Теребейчук”, step by step

StepLanguageWordMeaning
1Ukrainian-у́кAdded to an often diminutive stem to form a patronymic or matronymic surname
2Proto-Slavic*-ukъ—
Every word from Proto-Slavic *-ukъ →Every word from Ukrainian -у́к →