Regarding the initialism "SSBN": > The United States Navy's hull classification symbols for ballistic missile submarines are SSB and SSBN – the SS denotes subm

Regarding the initialism "SSBN": > The United States Navy's hull classification symbols for ballistic missile submarines are SSB and SSBN – the SS denotes submarine, the B denotes ballistic missile, and the N denotes that the submarine is nuclear powered. https://en.wikipedia.org/wiki/Ballistic_missile_submarine https://en.wikipedia.org/wiki/Ballistic_missile_submarine