A submarine-launched ballistic missile (SLBM) is a ballistic missile capable of being launched from submarines. Modern variants usually deliver multiple independently targetable reentry vehicles (MIRVs), each of which carries a nuclear warhead and allows a single launched missile to strike several targets.
It is a type of missile that is launched from a submarine, typically underwater, and travels through the atmosphere to deliver a nuclear warhead to a target on land or at sea. SLBMs are a key component of a country's nuclear deterrent, as they provide a second-strike capability in the event of a nuclear attack.
Some examples of SLBMs include the American Trident missile, the Russian Bulava missile, and the Chinese JL-2 missile. All of these are in active military service.