SSNs are also called attack submarines.

SSBNs are the big guys who carry large quantity of nuclear warhead ballistic missiles whose job is to lay low, stay hidden to maintain a first/second strike capability.

SSNs are the small guys who are fast and agile out on a hunt for enemy submarines. They also have limited capacity to launch cruise missiles on naval and land targets. Also known as the “fast attack subs”.

The Soviets/Russians also have SSGNs which are in between the two and capable of carrying long range guided cruise missiles, whose job is to stay hidden and then launch a large salvo of cruise missiles capable of overwhelming the enemy fleet’s defense.

Then you have the SSKs - the really small guys, the diesel-electric attack subs that operate on batteries and are extremely quiet but have limited range. They are usually built for littoral (coastal) defense rather than blue water naval power projection.

I’m guessing our subs are nuclear capable, because we’re the good guys, and their subs are nuclear attack subs, because they’re the bad guys.

Oh? I thought that was the term for these sorts of subs, I think it is to differentiate them from spying submarines that don’t carry weapons?