aetiology

/iหtษชหˆษ’lษ™dส’i/
noun
  1. 1

    The establishment of a cause, origin, or reason for something.

  2. 2

    The study of causes or causation.

  3. 3

    The study or investigation of the causes of disease; a scientific explanation for the origin of a disease.

Source: https://en.wiktionary.org/wiki/aetiology