The term "galleasses" refers to a type of large, multi-decked ship that was used primarily in the 16th century. These ships were notable for their large size and heavy armaments, which made them an effective weapon against enemy vessels. However, there are several synonyms that can be used to describe similar types of ships. For example, "galleys" were long, narrow ships that were used for both commerce and warfare. Another synonym is "war galleons," which were large, heavily armed sailing ships that were used by the Spanish Armada during the 16th century. Finally, "carracks" were a type of sailing ship that had three or four masts and were heavily armed.