in general, something belonging to a duke. See Duke.

The letters patent granted by the senate of Venice are called ducals: so also are the letters wrote, in the name of the senate, to foreign princes. The denomination of ducal is derived hence; that, at the beginning of such patents, the name of the duke or doge is wrote in capitals, thus, N—Dei Gratia Dux Venetiarum, &c. The date of ducals is usually in Latin, but the body is in Italian. A courier was dispatched with a ducal to the emperor, returning him thanks for renewing the treaty of alliance (in 1716), against the Turks, with the republic of Venice.