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.
Meaning 1: Patent = open/unblocked. Patent has a medical meaning of open or unblocked, particularly regarding an unblocked tube. Common usage includes a 'patent airway', or 'patent fallopian tubes'.eaning 1: Patent = open/unblocked. Patent has a medical meaning of open or unblocked, particularly regarding an unblocked tube. Common usage includes a 'patent airway', or 'patent fallopian tubes'.