Where does “ушче” come from?

ушче (Macedonian) comes from Proto-Slavic (j)ešče, from Proto-Indo-European *h₁esk(ʷ)e(h₁).

Ancestry of “ушче”, step by step

StepLanguageWordMeaning
1Proto-Slavic(j)eščestill, yet
2Proto-Indo-European*h₁esk(ʷ)e(h₁)—
Every word from Proto-Indo-European *h₁esk(ʷ)e(h₁) →Every word from Proto-Slavic (j)ešče →