Aetiology

1. n. The assignment of a cause.
2. n. The science, doctrine, or demonstration of causes; esp., the investigation of the causes of any disease; the science of the origin and development of things.

The word meanings were obtained from OPTED(The Online Plain Text English Dictionary), which is based on “The Project Gutenberg Etext of Webster’s Unabridged Dictionary” which is in turn based on the 1913 US Webster’s Unabridged Dictionary (See Project Gutenburg), as a text file.