A nuclear triad is a three-pronged military force structure of global-range land-based intercontinental ballistic missiles (ICBMs), submarine-launched ballistic missiles (SLBMs), and strategic bombers with nuclear bombs and missiles. More broadly, it can sometimes be used to mean any nuclear force with land, sea, and air basing, and more limited range. Countries build nuclear triads to eliminate an enemy's ability to destroy a nation's nuclear forces in a first-strike attack, which preserves their own ability to launch a second strike and therefore increases their nuclear deterrence.
Three countries are known to have a global-range triad: the United States, Russia, and China. While the US and the USSR (the predecessor state to Russia) acquired triads as part of the Cold War's nuclear arms race, operationalizing SLBMs during the 1960s, China achieved a viable triad in 2020 with its JL-1 air-launched ballistic missile.