The term "8 ball" of coke is also more privacy than the exact weight of the illegal drug. The reason it's named 8 ball is probably due to a possible connection with an 8-Ball game in Pools. It could also be due to the fact that the best cocaine is usually packed in larger chunks, or rocks, rather than powder like the one cut. In this case it's 1/8 an ounce "ball" of cocaine. The slang terms such as 8 ball blow been used as common terms for the 8 balls in cocaine powder.
