diagnoses

The identification of the nature and cause of an illness.

“He was given the wrong treatment due to an erroneous diagnosis.”

The identification of the nature and cause of something (of any nature).

A written description of a species or other taxon serving to distinguish that species from all others. Especially, a description written in Latin and published.

To determine which disease is causing a sick person's signs and symptoms; to find the diagnosis.

(by extension) To determine the cause of a problem.