Teleology is the study of things that happen for the sake of their future consequences.
Since nothing is ever actually the causal result of a future event, 'teleology' names a fallacy, that is, the fallacy of reasoning as if an event could be the result of a future event, its consequence.
A non-fallacious interpretation of teleology is as the study of things that happen because of their intended results, where the intention existed in an actual mind in the prior past, and so was causally able to bring about the event by planning and acting.