koo-tsóo高祖

great-great-grandfather

great-great-grandfather (paternal grandfather's paternal grandfather); primogenitor; remote ancestor

English Wiktionary, “高祖” (CC BY-SA 4.0) — https://en.wiktionary.org/wiki/%E9%AB%98%E7%A5%96 · confidence: Medium (Wiktionary, Hokkien)