The Brief: A "jar" refers to a quantity of 100 ecstasy or molly pills.
DEEP DIVE
The smaller quantity of ecstasy (E) or molly tablets that one might purchase from a plug is called a “jar.” The term derives from the phrase “jar full of”.
You still have a jar of ecstasy pills from '96 in your pantry https://t.co/6UxyeoZCSa
— Julian McCullough (@julezmac) May 11, 2016