​INVOICE (originally a plural, Invoyes or Invoys, of Invoy, a variant of “envoy,” from the French envoyer, to send), a statement giving full particulars of goods sent or shipped by a trader to a customer, with the quantity, quality and prices, and the charges upon them. Consular invoices, i.e. invoices signed at the port of shipment by a consul of the country to which the goods are being consigned, are generally demanded by those countries which impose ad valorem duties.