Mammoth Cave, the world's longest known cave system. The following is a list of the world's 10 longest caves per length of documented passageways. Many passageways are still being discovered; this list is based on the latest verifiable data.
patent medicine - medicine that is protected by a patent and available without a doctor's prescription. medicament, medication, medicinal drug, medicine - (medicine) something that treats or prevents or alleviates the symptoms of disease. nostrum - patent medicine whose efficacy is questionable.
The term âdrugâ refers to: 1  Prescription drugs which are licensed medicines that require a written order by a medical doctor or pharmacist before they can be obtained. 2  Certain poisonous (toxic) drugs and medicines may be subject to the requirements for Division 6.1 materials in Chapter 3.