Diagnosis \Di`ag*no"sis\, n.; pl. Diagnoses. [NL., fr. Gr. ?, fr. ? to distinguish; dia` through, asunder + ? to know. See Know.]

1. (Med.) The art or act of recognizing the presence of disease from its signs or symptoms, and deciding as to its character; also, the decision arrived at.

2. Scientific determination of any kind; the concise description of characterization of a species.

3. Critical perception or scrutiny; judgment based on such scrutiny; esp., perception of, or judgment concerning, motives and character.

The quick eye for effects, the clear diagnosis of men's minds, and the love of epigram. --Compton Reade.

My diagnosis of his character proved correct. --J. Payn.

Differential diagnosis (Med.), the determination of the distinguishing characteristics as between two similar diseases or conditions.

Source: Webster's Revised Unabridged Dictionary (1913)