eldfather

Etymology

From Middle English eldfader, variant of olde fader, from Old English eald fæder (“grandfather, ancestor”), equivalent to eld (“old”) + father. Cognate with Scots eldfader (“grandfather, father-in-law”), Old Frisian aldafeder (“grandfather”).

eldfather means one's grandfather or forefather. Lexicurio rates it Sui generis — a strength score of 88 out of 100.

Why “eldfather” is a great word

ELDFATHER — [Noun] An archaic term for a grandfather, forefather, or father-in-law. From Middle English eldfader, a variant of olde fader, from Old English eald fæder ("grandfather, ancestor"), equivalent to eld ("old") + father. Cognate with Scots eldfader and Old Frisian aldafeder. First attested in Old English. Unlike "grandfather," which precisely maps a genealogical position, or "patriarch," which exalts founding authority, eldfather is a more encompassing term of familial antiquity. It is the worn smoothness of a hearth-stone, the scent of loam and pipe smoke in a long-settled house, and the specific silence that follows a story told too many times to need an ending—a word for lineage not as power, but as quiet, accumulating weight in the old, familial dark.

noun

One's grandfather or forefather.“Elof sat with his eyes closed, still in the grip of the thought that he had just heard his eldfathers, all the way back to Adam, chanting at the table.”
One's father-in-law.