Where does “カッ” come from?

カッ (Japanese) comes from Korean 갓, from Old Chinese 芥.

Ancestry of “カッ”, step by step

StepLanguageWordMeaning
1Korean갓"gat"; a traditional Korean hat made of...
2Old Chinese芥—
Every word from Old Chinese 芥 →Every word from Korean 갓 →
カッ — Etymology, Origin & Word History | Etymology Explorer