Diagnostic \Di`ag*nos"tic\, a. [Gr. ? able to distinguish, fr. ?: cf. F. diagnostique.] Pertaining to, or furnishing, a diagnosis; indicating the nature of a disease.
Source: Webster's Revised Unabridged Dictionary (1913)
Diagnostic \Di`ag*nos"tic\, n. The mark or symptom by which one disease is known or distinguished from others.