Quasi posthumous child
Black's Law Dictionary · Henry Campbell Black, M.A. · 1910
Black's Law Dictionary
In the civil law. One who, bom during the life of his grandfather or other male ascendant, was not his heir at the time he made his testament, but who by the death of his father became his heir in hls life-time.
Inst. 2, 13, 2; Dig. 28, 3, 13.