Etiology is the study of causation or origination. The word is derived from the Greek αἰτιολογία (aitiología) "giving a reason for". More completely, etiology is the study of the causes, origins, or reasons behind the way that things are, or the way they function, or it can refer to the causes themselves. The word is commonly used in medicine and in philosophy, but also in physics, psychology, government, geography, spatial analysis, theology, and biology, in reference to the causes or origins of various phenomena.
