The term exogenous means that something is formed from external causes or from the outside of a system works out inward or outward. The opposite is endogenous. These terms refer to different sciences use.


The word is from the Greek word elements exo ( gr ἔξω ) for "to", " of ", " outside", " outside " and the suffix -tions together. Therefore exogenous means something is out or is caused by external causes. When the term is used in the natural sciences and medicine, it refers generally to arising outside the body, penetrating from the outside into the organism, arising from external causes, externally to the body interacting. This can for example describe materials, substances, bacteria, viruses, or procedures. The term is exogenous but also used in other subject areas.

Use in various sciences

  • In the archeology of the Stone Ages, the raw material, is produced from the stone artifacts, referred to as exogenous, if it does not occur at the point of reference.
  • In botany exogenous plant parts are those parts of a plant resulting from tissue layers at the surface of the plant out and not in the interior of the plant.
  • In geology exogenous processes are the ones that caused by externally applied forces such as gravity and solar radiation at the earth's surface run off, including erosion.
  • In medicine exogenous causes of diseases such as pathogens or substances which penetrate from the outside into the organism.
  • In politics are exogenous and endogenous causes of poverty: exogenous causes are factors that come from the outside; are endogenous factors that are rooted in the interior of the country.
  • In psychiatry, it is called exogenous factors, if the causes of psychosis, for example, when poisons or other external influences are to be found.
  • The psychology speaks of exogenous factors or processes if they arise from external causes and effects out and not by design, yet are inherited.
  • In statistics indicate exogenous variables factors, from which manifest themselves differently in a causal or structural equation model, the expression of an endogenous variable to be explained or predicted.
  • In economics variables are called exogenous if they represent an independent variable in a model. Exogenous variables are those variables so that a model that can be chosen and changed freely, with which, therefore, the endogenous variables in a model can be influenced.