In different eras, the roles and capabilities of ships classified as frigates have varied. The name frigate in the 17th to early 18th centuries was given to any full-rigged ship built for speed and maneuverability, intended to be used in scouting, escort and patrol roles. The term was applied loosely to ships varying greatly in design. In the second quarter of the 18th century, what is now generally regarded as the 'true frigate' was developed in France.
This type of vessel was characterised by possessing only one armed deck, with an unarmed deck below it used for berthing the crew. Late in the 19th century British and French prototypes were constructed in , a type of powerful ironclad warships was developed, and because they had a single gun deck , the term 'frigate' was used to describe them.
Later developments in ironclad ships rendered the 'frigate' designation obsolete and the term fell out of favour. During the Second World War , the name 'frigate' was reintroduced to describe a seagoing escort ship that was intermediate in size between a corvette and a destroyer.
After World War II, a wide variety of ships have been classified as frigates, and the reasons for such classification have not been consistent. While some navies have used the word 'frigate' principally for large ocean-going anti-submarine warfare ASW combatants, others have used the term to describe ships that are otherwise recognizable as corvettes, destroyers, and even nuclear-powered guided-missile cruisers.
Some European navies use the term for ships that would formerly have been called destroyers, as well as for frigates. The etymology of the word remains uncertain, although it may have originated as a corruption of aphractus , a Latin word for an open vessel with no lower deck.
