Where does “Thi” come from?

Thi (English) comes from Vietnamese thì, from Chinese 時, from Old Chinese 之.

Ancestry of “Thi”, step by step

StepLanguageWordMeaning
1VietnamesethìDated form of thời; the prime time in terms of...
2Chinese時—
3Old Chinese之—
Every word from Old Chinese 之 →Every word from Chinese 時 →Every word from Vietnamese thì →
Thi — Etymology, Origin & Word History | Etymology Explorer