2-4-14 is a reference to the Black Disciples Nation gang. BDN is one of the many abbreviation the Black Disciples used, sometimes BDN is switched for 2-4-14 which is essentially the same thing. B is the 2nd letter in the alphabet, D is the 4th letter in the alphabet, and N is the 14th letter in the alphabet, hence the term 2-4-14. Black Disciples gang member sometime use "BD" as an abbreviation, so it's just "2-4".