thài-chó͘-kong太祖公

great-great-grandfather

great-great-grandfather (paternal grandfather's paternal grandfather)

English Wiktionary, “太祖公” (CC BY-SA 4.0) — https://en.wiktionary.org/wiki/%E5%A4%AA%E7%A5%96%E5%85%AC · confidence: Medium (Wiktionary)