Which term refers to a disease of unknown cause?

The term "idiopathic" specifically refers to a condition or disease for which there is no known cause. In medical terminology, when a disease is described as idiopathic, it signifies that despite thorough examination and testing, the underlying reason for its occurrence remains elusive. This can be seen in conditions such as idiopathic pulmonary fibrosis or idiopathic epilepsy, where symptoms present clearly, but the origin or trigger of the disease cannot be identified.

The other terms do not convey the same meaning. "Symptomatic" refers to something that is related to or characterized by symptoms, indicating that there are observable signs associated with a condition. "Chronic" describes a disease that persists for a long time, often for the remainder of a person's life, while "acute" describes a disease or condition that arises suddenly and is typically severe in nature but not necessarily long-lasting. Understanding these distinctions emphasizes why "idiopathic" is the appropriate term when discussing diseases without a known cause.