Merriam-Webster Collegiate Dictionary - courtesy

 I. noun  (plural -sies)  Etymology: Middle English corteisie, from Anglo-French curteisie, from curteis  Date: 13th century  1.  a. courteous behavior  b. a courteous act or expression  2.  a. general allowance despite facts ; indulgence hills called mountains by ~ only  b. consideration, cooperation, and generosity in providing something (as a gift or privilege); also agency, means — used chiefly in the phrases through the ~ of or by ~ of or sometimes simply ~ of  II. adjective  Date: 1613 granted, provided, or performed as a ~ or by way of ~ made a ~ call on the ambassador