A great-grandfather’s grandmother’s sister, (ataviae soror;) called by Bracton “atmatertcra magna” Bract, fob 6Sb Source: Black’s Law Dictionary 2nd Ed (1910)
The great-grandfather’s or great-grandmother’s grandfather; a fourth grandfather. The ascendlng line of llneal ancestry runs thus: Pater, Avus, Proavus, Abacus, Atavus, Tritavus. […]