Apex The summit or highest point of anything; the top; e. g., in mining law, “apex of a vein." See Larkin v. Upton, 144 U. S. 19, 12 Sup. Ct. 614, 36 L. Ed. 330; Stevens v. williams, 23 Fed. Cas. 40; Dug-gan v. Davey, 4 Dak. 110. 26 N. W. 887 Source: Black's Law Dictionary 2nd Ed (1910)