According to The Free Dictionary, etiology, also spelled aetiology, is the study of exploration of the cause or factors contributing to something. In pathology, it specifically denotes the investigation into the cause or origins of a disease.
According to Dictionary.com, the noun etiology comes from the Ancient Greek word "??????????," or aitiologia, from "?????," or "aitia," meaning cause. The suffix "-logy" denotes that the term refers to an area of scientific study or a specific body of knowledge. It was originally used in English during the 16th century. It is primarily used as a term in medicine, specifically pathology, meaning the investigation of the scientific cause of an illness or disease.