www.lesswrong.com/posts/hiiguxJ2EtfSzAevj/are-there-lessons-from-high-reliabilit...

In standard military/technical terminology, an ICBM (“intercontinental ballistic missile”) is a land-based ballistic missile with intercontinental range, while ballistic missiles launched from submarines are SLBMs (“submarine-launched ballistic missiles”).

Britannica’s definition of ICBM explicitly states that an ICBM is land-based, and then separately notes that SLBMs can have ranges comparable to ICBMs (e.g., Trident). That means calling something a “submarine-launched … ICBM” is a category error: submarine-launched ballistic missiles are not ICBMs; they are SLBMs (even if they have intercontinental range).

Additionally, the U.S. Office of the Secretary of Defense’s New START treaty definitions treat ICBMs and SLBMs as distinct categories and explicitly define “submarine-launched ballistic missile (SLBM)” as a missile “contained in, or launched from, a submarine,” reinforcing the standard distinction in official usage.