What is Avail Of Marriage?

Legal Definition
In feudal law. The right of marriage, which the lord or guardian in chivalry had of disposing of his infant ward in matrimony. A guardian In socage had also the same right, but not attended with the same advantage. 2 Bl. Comm. 88. In Scotch law. A cortain sum due by the heir of a deceased ward vassal, when the heir became of marriageable age. Ersk. Inst. 2, 5, 18.
-- Black's Law Dictionary
Legal Definition
Value of marriage, i. e., what the suitor would give.
-- Ballentine's Law Dictionary