What does ounce mean?
An ounce is a for sure a weight, but in the cannabis world in the USA an ounce is a prized possession of 28 grams of cannabis.
More info on an ounce
There are 16 ounces in a pound of marijuana. Many times cannabis is sold as 1/8 ounces, 1/4 ounces, 1/2 ounces and full ounces. There are also 28 grams in an ounce.
Cannabis Encyclopedia