CoD = Call Of Duty, which is a popular video game for the Xbox 360, PS3, Wii, and PC.
CoD 5 is the incorrect way to say Call Of Duty: World At War.(WaW) People say CoD 5 because they are too lazy to say CoD: WaW.
Friend 1:"Hey dude, lets go play some cod 5."
Friend 2:"Don't you mean cod: waw?"
Friend 1:"Same thing!"