Mediate Descent Law and Legal Definition

A descent from the grandfather, who dies in possession, to the grandchild, the father being then dead, or from the uncle to the nephew, the brother being dead, is in law a mediate descent. The father and the brother is the medium deferens since they are the medium, through or by whom the son or nephew derives his title to the grandfather or uncle. [Levy v. M'Cartee, 31 U.S. 102, 113 (U.S. 1832)].