di·ag·no·sis 
(dī′əg-nōsĭs)
(dī′əg-nōsĭs)n. pl. di·ag·no·ses (-sēz)
1. Medicine
a. The act or process of identifying or determining the nature and cause of a disease or injury through evaluation of patient history, examination, and review of laboratory data.
b. The opinion derived from such an evaluation.
2.
a. A critical analysis of the nature of something.
b. The conclusion reached by such analysis.
3. Biology A brief description of the distinguishing characteristics of an organism, as for taxonomic classification.
[Greek diagnōsis, discernment, from diagignōskein, to distinguish : dia-, apart; see DIA- + gignōskein, gnō-, to come to know, discern; see gnō- in the Appendix of Indo-European roots.]