Abamita

Lat in the civil law. A great-great-grandfather's sister, (abavi soror.) Inst 3, 6^ 6; Dig. 38, 10, 3. Called amita maxima. Id. 38, 10, 10, 17. Called, in Brac* ton, abamita magna. Bract fol. 68b

Source: Black's Law Dictionary 2nd Ed (1910)