But I know y'all wanted that 808 / can you feel that B-A-S-S, bass? -- Outkast's overplayed late 2003 song "The Way You Move"

Eight-oh-eight is urban parlance for an especially loud sound system, particularly one with a lot of bass, as well as the aural effects that come from it.

Like a great deal of slang, the etymology of this particular term is shrouded in unreliable reports that those espousing them nonetheless swear to the absolute truth of; the most popular are that it either comes from the ubiquitous Roland TR-808 drum machine, used by rappers as old school as the Sugar Hill Gang, or from the police code for violation of noise pollution laws. The first legend is the most plausible, but the second is quoted often enough that it also needs to be mentioned. Also note the lexical drift: it would seem to make more sense for the term to refer to an old school bassline rather than a loud stereo, but that is not how it is generally used.

This palindrome is also the area code for Hawaii, the "808 State."