Etiology (alternatively aetiology, aitiology)'s the study of causation. The word's derived from the Greek, aitiologia, "giving a reason for" (aitia, "cause"; and, -logia). The word's most commonly used in medical and philosophical theories, where it's used to refer to the study of why things occur, or even the reasons behind the way that things act, and's used in philosophy, physics, psychology, government, medicine, theology and biology in reference to the causes of various phenomena. An etio… (More on Etiology)