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.
A generic drug is a copy of a brand name drug whose patent has expired. The original manufacturer of a drug receives a patent on the drug and is the only manufacturer who can produce and sell the drug during this patent period. Once the patent expires, other manufacturers may produce and sell the drug. These manufacturers usually sell the drug under its common or generic name. Most drugs have three names: 1  a chemical name. 2  a generic name. 3  a brand name.