A glass jar that may contain many sorts of alcoholic beverages (mainly Ryan Cokes) and may or may not have a handle. True Jam Jars should be able to hold a full mickey. After indulging in a series of Jam Jars, comical events tend to happen.
"I've had like...7 fucking Jam Jars..."
"Let's get some Jam Jars, or play Bag Face"
Large glasses with thick lenses, often considered nerdy or geeky. Sometimes referred to as coke bottles.
Cool Kid 1: Eugh, look at that dweeb with the jam jars.
Cool Kid 2: Gag me. I wouldn't be caught dead wearing those.