Jenny Crank n. methamphetamine, especially in the phrase Jenny Crank diet, a jocular term for weight loss caused by use of the drug or similar drugs. Etymological Note: A play on Jenny Craig, a popular weight-loss program. Occasionally, Jenny Crank is used to refer only to the Jenny Craig meal plan and not to the drug. Crank is one of the many slang names for methamphetamine, most commonly known as crystal meth or meth. (source: Double-Tongued Dictionary)