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.
Patents:A patent is a legal document granting its holder the exclusive right to control the use of an inven-. tion, as set forth in the patentâs claims, within a limited area and time by stopping others from, among other. things, making, using or selling the invention without authorization.