cruiser
A middle-large type of warship, so named for being a cruising warship. Smaller than a battleship, larger than a destroyer. Existed from mid-19th century to late 20th century until their role more or less completely fused together with that of a guided missile destroyer.
Various subtypes of cruisers throughout the ages:
- Unprotected cruiser - a type of late 19th century cruiser characterized by its complete or almost complete lack of armor, usually either meant to serve as a colonial gunboat where it hopefully wouldn't run into anything too dangerous, scout cruiser for bigger ships, or as a leader for torpedo boat and/or destroyer flotillas. Example: German SMS Geier that was seized by United States during WW1 and renamed USS Schurz.
- Protected cruiser (hull code C) - a type of late 19th century cruiser that lacked armored belt but had its vital spaces protected by a combination of armored deck and coal bunkers. Protected cruisers could vary size significantly small couple thousand ton ships serving in similar roles as unprotected cruisers to 11 000 ton behemoths like British Diadem-class. Example: USS Olympia (C-6) that is preserved as a museum ship in Philadelphia.
- Armored cruiser (hull code ARC, later CA) - a type of late 19th century cruiser that had both armored belt and deck to protect its vitals. Armored cruisers and protected cruisers co-existed for a while but as the time went on and rapid firing guns and exploding shells started to get more common armored cruisers became the dominant type when it came to large cruisers with protected cruisers being relegated to medium and small sized roles. As the time went on armored cruisers started to evolve into fast, lightly armed 2nd rate battleships, a role in which Japanese successfully used their armored cruisers during the Russo-Japanese War. Ultimately this and advances in engine technology and adaption of oil firing lead to armored cruiser lineage splitting into two: small lightly armored cruisers (also known as light cruisers) and bigger, heavier battlecruisers carrying guns similar to those as on battleships. Example: Greek Georgios Averof, the sole surviving armored cruiser.
- Battlecruiser (hull code CC) - a type of WW1&WW2 capital ship that evolved from armored cruisers, were used in large numbers by German and British navies during WW1 but by WW2 they basically had gone extinct with only 4 Japanese Kongou-class, 2 British Renown-Class and 1 Admiral-class, and Turkish Yavuz (originally SMS Goeben) still being in service. Roles envisioned for battlecruisers were heavy scouting, elimination of of enemy armored cruisers, and 2nd rate battleship roles during WW1 and cruiser killing, carrier escorting, shore bombardment, and light fast battleship role during WW2. Example: HMS Tiger, the most modern British battlecruiser at start of the WW1, the largest ship in Royal Navy by displacement until HMS Hood entered service (making her also the largest ship to take part in the Battle of Jutland), and a Kongou lookalike.
- Light cruiser (hull code CL) - also known as lightly armored cruiser these ships evolved from smaller armored cruisers and took over the roles traditionally held by protected and unprotected cruisers. Due to adaption of oil firing and advances in armor manufacturing it became possible to build small cruisers that were capable of both carrying deck&belt armor while still capable of reaching high speeds needed for scouting and destroyer squadron leading. Light cruisers were mostly restricted to these roles during WW1 but by WW2 they had also acquired new roles such as working as 3rd rate battleships when there weren't real battleships or battlecruisers around (a role mostly reserved for larger light cruisers such as American Cleaveland-class), commerce raiding, screening units for bigger ships, and super-heavy destroyer. For example: USS Little Rock (CL-92/CG-4) a WW2-era heavy light cruiser converted to guided missile cruiser and HMS Caroline a more traditional WW1-era light cruiser.
- Heavy cruiser (hull code CA) - evolved from light cruisers during WW1 but only really saw action during WW2, while light cruisers usually were limited to guns around 6" or smaller following the 1st London Naval Treaty (before this both cruisers armed with 6" or smaller and 8" guns were lumped in same category as far cruiser tonnage was concerned) heavy cruisers tended to carry guns around 8" in size which, in theory at least, was meant to help them counter light cruisers. Generally heavy cruisers were used in similar roles as larger light cruisers and performance wise weren't any more or less effective than larger CLs. Example: USS Salem (CA-139) the last heavy cruiser to enter service and the sole remaining example of the type.
- Super-heavy/Large cruiser (hull code CB) - due to various naval treaties more or less equalizing the playing field when it came to cruiser size and armament (outside of couple outliers such as German Deutchland-class panzerschiffe/heavy cruisers/pocket battleships that carried 11" guns) the idea of building bigger and significantly more heavily armed to counter these was considered by multiple navies. This tended to create designs for ships that looked pretty similar to old battlecruisers still lying around in various stages of modernization (with old battlecruisers usually having the advantage of mounting bigger guns) and to this day people still argue whether or whether not battlecruiser and super-heavy/large cruiser are synonyms. Ultimately while multiple navies considered building super-heavy cruisers only Americans did so. Example: USS Alaska (CB-1), the nameship of the sole class of super-heavy cruisers built, saw limited amount of combat during the later stages of WW2 before being mothballed soon afterwards and ultimately scrapped during early 1960s, the short lifespan of Alaska-class (and probably why no other examples of said ship type were built) can probably be explained by following: in both operating&building costs and capabilities Alaskas inhabited the awkward middle ground between Baltimore-class heavy cruiser and Iowa-class fast battleships which meant that there really wasn't ever any real meaningful role for them to occupy in USN.
- Guided-missile cruiser (hull code CG) - a cruiser carrying guided-missiles, common during Cold War but nowadays only in service in Russian and American navies, the first examples of this type were usually converted from old WW2-era cruisers but as time went on purpose built missile cruisers became more common. Nowadays the roles of guided-missile cruisers and guided-missile destroyers have more or less completely fused together with the cruiser designation only being used for handful of old ships built during the Cold War. Example: Soviet/Russian Kirov-class nuclear powered guided-missile cruiser Pyotr Velikiy.