diagnosis

Etymology

From Latin diagnōsis, from Ancient Greek διάγνωσις (diágnōsis), from διαγιγνώσκω (diagignṓskō, “to discern”), from διά (diá, “through”) + γιγνώσκω (gignṓskō, “to know”).

noun

1. (medicine) The identification of the nature and cause of an illness.
   He was given the wrong treatment due to an erroneous diagnosis.
   In an era when political leaders promise deliverance from decline through America’s purported preeminence in scientific research, the news that science is in deep trouble in the United States has been as unwelcome as a diagnosis of leukemia following the loss of health insurance. 2012-01, Philip E. Mirowski, “Harms to Health from the Pursuit of Profits”, in American Scientist, volume 100, number 1, archived from the original on 2012-04-04, page 87
2. The identification of the nature and cause of something (of any nature).
   The quick eye for effects, the clear diagnosis of men's minds, and the love of epigram. 1887, Charles L. Reade, Compton Reade, Charles Reade, Dramatist, Novelist, Journalist: A Memoir
   My diagnosis of his character proved correct. 1887, James Payn, Glow-worm tales
3. (taxonomy) A written description of a species or other taxon serving to distinguish that species from all others; especially a description written and published in Latin.

verb

1. (nonstandard, proscribed, rare) Synonym of diagnose
   Experienced mechanics can diagnosis the condition of machinery just by listening. 2013, Donald A. Norman, The Design of Everyday Things