Dictionary.net

Something claimed by royal right, as a charge on metal brought to the royal mint to be coined; a share of the receipts of a business taken in payment for the use of a right, as a copyright or patent.

A governmental charge for coining bullion.

The difference between the cost of bullion and the nominal value of the coin made from it.

A royalty or a commission on sales.

A royal prerogative by which the sovereign anciently claimed a percentage on all the gold and silver brought to the Mint for coinage; the profit derived from issuing coins at a rate above their intrinsic value; a royalty.

A charge levied on bullion brought by private individuals to the mint to be coined, which is effected by giving back rather less in coin than was received in bullion, only sufficient in amount to cover the expense-in England the coin age of bullion is generally done at the public expense, but there is a large seigniorage levied on silver and copper currencies; formerly a specific tax on bullion as well as on silver and copper coinage, forming a branch of the royal revenue; acknowledgment of power.

n. Something claimed or taken by virtue of sovereign prerogative; specifically, a certain toll or deduction on bullion brought to the mint to be coined.