A polacca is a type of seventeenth-century sailing vessel, similar to the xebec

Xebec

A xebec , also spelled zebec, was a Mediterranean sailing ship that was used mostly for trading. It would have a long overhanging bowsprit and protruding mizzen mast...

. The name is the feminine of "Polish" in the Italian language

Italian language

Italian is a Romance language spoken mainly in Europe: Italy, Switzerland, San Marino, Vatican City, by minorities in Malta, Monaco, Croatia, Slovenia, France, Libya, Eritrea, and Somalia, and by immigrant communities in the Americas and Australia...

. The polacca was frequently seen in the Mediterranean. It had three single-pole masts

Mast (sailing)

The mast of a sailing vessel is a tall, vertical, or near vertical, spar, or arrangement of spars, which supports the sails. Large ships have several masts, with the size and configuration depending on the style of ship...

, often with a lateen

Lateen

A lateen or latin-rig is a triangular sail set on a long yard mounted at an angle on the mast, and running in a fore-and-aft direction....

 hoisted on the foremast (which was slanted forward to accommodate the large lateen yard) and a gaff

Gaff

-Pole-shaped devices:* Fishing gaff, a pole used in fishing* Gaff or hakapik, used as a seal-hunting weapon* Gaff rig; A fore-and-aft sailing arrangement where the sail is held up by a spar called a gaff-Ankle-worn devices:...

 or lateen on the mizzen mast. The mainmast was square-rigged after the European style. Special polaccas were used by Murat Reis

Jan Janszoon

Jan Janszoon van Haarlem, commonly known as Murat Reis the younger was the first President and Grand Admiral of the Corsair Republic of Salé, Governor of Oualidia, and a Dutch pirate, one of the most notorious of the Barbary pirates from the 17th century; the most famous of the "Salé...

, whose ships had lateen sails in front and Fore-and-aft rig

Fore-and-aft rig

A fore-and-aft rig is a sailing rig consisting mainly of sails that are set along the line of the keel rather than perpendicular to it. Such sails are described as fore-and-aft rigged....

 behind.

Some polacca pictures show what appears to be a ship-rigged

Full rigged ship

A full rigged ship or fully rigged ship is a sailing vessel with three or more masts, all of them square rigged. A full rigged ship is said to have a ship rig....

 vessel (sometimes with a lateen on the mizzen) with a galley-like hull

Hull (watercraft)

A hull is the watertight body of a ship or boat. Above the hull is the superstructure and/or deckhouse, where present. The line where the hull meets the water surface is called the waterline.The structure of the hull varies depending on the vessel type...

and single-pole masts. Thus, the term "polacca" seems to refer primarily to the masting and possibly the hull type as opposed to the type of rig used for the sails.