Mint-Mark
Bouvier's Law Dictionary and Concise Encyclopedia · John Bouvier; revised by Francis Rawle · 1914
Bouvier's Law Dictionary and Concise Encyclopedia
The masfers and workers of the mint, in the indentures made with them, agree to make a privy - mark in the money they make, of gold and silver, so that they may know which moneys were of their own making; after every trial of the pix, having proved their moneys to be lawful, they are entitled to their quietus under the Great Seal, and to be thereanent discharged from all suits or actions; they then change the privy mark, so that the moneys from which they are not yet discharged may be distinguished from those for which they are; they use the new mark until another trial of the pix.
Wharton.