"P.S.K. What Does It Mean?" (also written as "P.S.K. (What Does It Mean?)") is a song released in 1985 by Philadelphia rapper Schoolly D on his independent label Schoolly D Records. P.S.K. are the initials for Park Side Killas, a street gang with which Schoolly D was affiliated. The highly influential song is considered the first hardcore rap song and features incidents of graphic sex, gunplay, drug references and one of the first uses of the word "nigga" in a rap song (Grandmaster Flash & the Furious Five had used the word in the 1983 song New York, New York and Ice-T had used it in the 1983 song The Coldest Rap).
It would be critical to the rise of West Coast gangsta rap when the street hustler, gang member and upcoming rapper by the name of Ice-T released his hardcore anthem "6 in the Mornin'" that he has admitted in interviews was written after he heard Schoolly D's "P.S.K." Eazy-E's first song "Boyz-N-The-Hood is also heavily influenced by "P.S.K." Another fan of the song is musician Moby and Danny Diablo, who covered it with the Lordz of Brooklyn.