The Arms and the Talks: A Glossary

The field of arms control is cluttered with jargon, acronyms and initials. Here is a guide to the more important and inescapable terms:

ABM: Antiballistic missile, a defensive weapon that can shoot down incoming offensive ones.

CRUISE MISSILE: A jet-powered drone that flies, or "cruises," through the atmosphere, rather than arcing into space on a ballistic trajectory, like a rocket. The cruise missile finds its way to a target by matching the terrain over which it flies against a map stored in its computerized brain. Because it is small (about 18 ft. long) and flies very low, it is difficult for the Air-launched cruise missile (ALCM) on test flight enemy to track and intercept. There are three varieties: the air-launched cruise missile, ALCM (pronounced al-kum), which is fired from a bomber, and the GLCM (glickum) and SLCM (slickum), the ground-and sea-launched versions of the same weapon.

ICBM: Intercontinental ballistic missile, a rocket usually intended to be fired from an underground silo in the U.S. or U.S.S.R. that can reach the territory of the other superpower. It is the most destructive of strategic weapons, but also the most vulnerable, since until it is fired, it is stationary and can be fairly easily targeted by the other side. The principal American ICBM is the Minuteman III, with three warheads; the main Soviet ones are the SS-18, with ten warheads, and the SS-19, with six.

INF: Intermediate-range Nuclear Forces, a term that refers to American weapons in Europe that can reach the U.S.S.R. and Soviet weapons targeted against Western Europe. The superpowers began negotiating about INF, then called Theater Nuclear Forces, in 1980.

MIRV: Multiple independently targetable re-entry vehicle, one of a cluster of nuclear warheads mounted on a single missile that can be hurled at different targets.

MX: "Missile-experimental," a large, ten-warhead ICBM that the U.S. is developing as an eventual successor to the Minuteman and as a counter to the Soviet SS-18 and SS-19.

SALT: Strategic Arms Limitation Talks, negotiations that began early in the "Nixon Administration, producing the 1972 SALT I treaty limiting ABMs and an interim agreement restricting offensive weapons, and ended with the 1979 SALT II treaty, signed by Jimmy Carter and Leonid Brezhnev but never ratified by the U.S. Senate.

SLBM: Submarine-launched ballistic missile. American submarines are harder for the Soviets to track than the other way around, and American SLBMS are more accurate and reliable than their Soviet counterparts.

START: Strategic Arms Reduction Talks, the Reagan Administration's arms-control negotiations that attempt to improve on the terms of SALT.