Teleology: It is the study of interpretations of structures in terms of utility and purpose. Teleology is philosophical account that holds the final causes exist in nature, meaning that design and purpose analogous to which found in human actions are inherent also in the rest of nature. The adjective that is "teleological" has a broader usage, for example in discussions where particular ethical theories or kinds of computer programs like as "teleo-reactive" programs, are sometimes described as teleological because they involve aiming at goals.
Teleology was explored by Aristotle or Plato, by Saint Anselm around 1000 AD. A thing, action or process is teleological when it is for the sake of an end, that is a telos & final cause. In common it can be said that there are two kinds of final causes, which can be called intrinsic finality or extrinsic finality. A thing or action can have an extrinsic finality when it is for the sake of something external to itself. If the external thing had not existed then action would not display finality.