During the late 1600's the British Fleet built a three masted "light nimble ship built with the purpose of sailing swiftly." Fast and powerful enough to capture merchantmen and elude heavier warships, it was called a frigate, a term derived from the earlier Italian word fregata.
The fregata had been a long narrow merchant ship propelled by sails or oars and was common in the Mediterranean during the 16th and 17th Centuries. Toward the end of the 18th Century, the term frigate had crystalized. It identified a two deck ship with the main, or gundeck, and the upper deck, which had no name until U.S. Navy Sailors christened it the spar deck.
In earlier times, British frigates were used to forewarn homeward bound merchantmen and to escort convoys across the Atlantic and the North Sea. U.S. Navy frigates built during the 1790's were larger than those built by the British. They were also principally employed for scouting and convoy duty.