Definition of: etiology

(ē′tē·ol′ə·jē) noun
1. The science of efficient, as distinguished from final, causes.
2. That department of medicine that treats of the causes of disease.
3. The giving of a cause or reason for anything; also, the reason itself. Also spelled aetiology. [<LL aetiologia <Gk. aitiologia <aitia cause + logos word, study]
—e·ti·o·log·i·cal (ē′tē·ə·loj′i·kəl) adjective
—e′ti·o·log′i·cal·ly adverb
—e′ti·ol′o·gist noun