Caucasian originally was a geographical reference, meaning relative or pertaining to the Caucasus region of eastern Europe, a region between the Black and Caspian seas that includes southwest Russia, Georgia, Azerbaijan, and Armenia, and that forms part of the traditional boundary between Europe and Asia. Over time, it has included other meanings.
In the context of forensic anthropology and censuses, Caucasian is a specific combination of physical attributes, especially white skin. In the USA, Canada, and Australia, Caucasian is commonly used to refer to light-complexioned people indigenous to, or descended from Europe, northern Africa, southwest Asia, and the Indian subcontinent. In North America, Caucasian usually means a white person of northern, southern, eastern, and western European, Middle Eastern, and North African descent, excluding people with significant Asian, African, or American Indian ancestry.