A carrack or nao was a three or four-masted sailing ship developed in the Mediterranean in the 15th century. It had a high rounded stern with an aftcastle and a forecastle and bowsprit at the stem. It was square-rigged on the foremast and mainmast and lateen-rigged on the mizzenmast.
Carracks were the first proper ocean-going ships in Europe: large enough to be stable in heavy seas, and roomy enough to carry provisions for long voyages. They were the ships in which the Spanish and Portuguese explored the world in the 15th and 16th centuries. In Spanish this type was called "nao", while in Portuguese it was called "nau" (which meant "ship").
Famous carracks are the Santa Maria in which Christopher Columbus made his voyage in 1492, and Henry VIII's Mary Rose.
During the 16th century the carrack developed into the galleon.
The book The Galleon (1990), Conway Maritime Press, ISBN 0851775662, contains excellent description and commentary on galleons and carracks.
Other types of sailing vessel