What is 8+1?
A gun, specifically a 9 milimeter (8+1=9). Used frequently in rap music.
In the Wu-Tang Clan's song "Da Mystery of Chessboxin'" Ghostface Killah proclaims "So grab your 8+1, start flippin and trippin/Niggaz is jettin i'm lickin off son"
See gun, gat, glock, beretta