A warship is a vessel built to take an active part in naval warfare, carrying out missions principally including anti-surface warfare, anti-air warfare, anti-submarine warfare and land attack. While technically warships, vessels purpose-built for mine warfare and amphibious warfare have defensive weapons only.
The term "man o'war" has been used historically for worships, but does not imply a purpose-built design. Underlying design is important in modern warships; there is a delicate argument for certain escorts that are built on merchant hulls but still have some purpose-built features. Not all naval ships that engage in combat are warships, such as armed merchant cruisers or early pirate vessels.
The major modern types of warships are of the types:
- Aircraft carrier : A warship designed to launch and recover combat aircraft and aircraft that support military operations
- Cruiser : While definitions vary with time and doctrine, a large warship capable of acting independently, as a flagship, or a major escort; capabilities include anti-air warfare, anti-surface warfare, anti-submarine warfare, land attack, and possibly ballistic missile defense
- Destroyer : While the definition has evolved constantly, it is a multipurpose surface warship, generally less powerful than a cruiser, with capabilities against ship, aircraft, submarine, land, and sometimes ballistic missile targets
- Ocean escort : A warship with weapons and sensors to defend itself and ships near it, sturdy enough to operate in ocean conditions, but with only enough speed to escort merchant and military support ships, and usually not built to full warship standards of battle damage survivability
- Fast attack craft : Small naval craft, used in coastal waters, which rely on speed and maneuverability to survive to deliver heavy weapons (e.g., torpedoes, anti-shipping missiles) against warships, or to make gunfire attacks on merchant ships and landing craft
- Submarine : A ship or boat that can travel underwater
- Corvette : In modern use, a multipurpose warship intended principally for coastal use, although more like a small destroyer for patrol work than a fast attack craft; corvettes may be capable of ocean escort duty but typically have less endurance
Historical types of warships included:
- Battleship : A heavily-armored, warship optimized for fighting other warships using large-caliber guns; certain armor requirements differentiated from cruisers; obsolete by end of World War II.
- Battlecruiser : A large warship with guns comparable to those of a battleship, equal or greater speed, but less armor; "can catch what it can kill and run away from what can kill it"; had disastrous experiences when fighting true battleships
- Frigate : Add brief definition or description
- Trireme : Add brief definition or description
- Monitor : An armored warship, possibly limited to coastal waters, with large-caliber guns in one or more turrets