What term refers to the study of the cause or nature of a disease?

The accurate term for the study of the cause or nature of a disease is "pathology." Pathology involves examining the structural and functional changes in tissues and organs that lead to disease manifestations. It plays a crucial role in medical diagnostics, as it helps in understanding how diseases develop and progress, which in turn aids in establishing diagnoses and determining appropriate treatments.

Pathophysiology, while related, focuses more on the changes in body systems that occur as a result of the disease process rather than specifically studying the disease itself. Pediatrics, on the other hand, is a branch of medicine that deals with the medical care of infants, children, and adolescents, and does not pertain to the study of disease causes. Patient rights refer to the legal entitlements of patients regarding their healthcare, which is unrelated to the scientific study of diseases. Thus, pathology is the correct answer because it specifically addresses the investigation of disease origins and characteristics.