Main Page | See live article | Alphabetical index SSN is an acronym for 'Social Security Number', used by Social Security (United States). It is also the hull classification symbol used by the United States Navy for an attack submarine that is propelled by nuclear energy, such as the Los Angeles-class attack submarines of attack submarines. See also: SS, SSBN, Submarine This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License.