Anorexia (deriving from the Greek "α(ν)-" (a(n)-, a prefix that denotes absence) + "όρεξη (orexe) = appetite) is the decreased sensation of appetite. While the term in non-scientific publications is often used interchangeably with anorexia nervosa, many possible causes exist for a decreased appetite, some of which may be harmless, while others indicate a serious clinical condition, or pose a significant risk.