tin
n.— «Jessica said those who know where to go can buy heroin in Chicago at $10 a tin, or blow—about one-tenth of a gram.…”Tin” refers to the way the powder is packaged in small tinfoil squares.» —“LaSalle County facing truth of youth heroin use” by Jessica L. Aberle Journal Star (Ottawa, Can.) May 22, 2005. (source: Double-Tongued Dictionary)