noun
great-great-grandfather
Refers to the grandfather of one's grandparent. A formal kinship term; in casual conversation, people may simply say ひいひいおじいさん.
高祖父は明治時代に生まれました。
My great-great-grandfather was born in the Meiji era.
A more colloquial and child-friendly way to say great-great-grandfather, while 高祖父 is formal and often used in written or genealogical contexts.
Compound of 高 (great, high) and 祖父 (grandfather). The prefix 高 indicates a generation beyond 曽祖父 (great-grandfather).