a. [ Gr. &unr_; able to distinguish, fr. &unr_;: cf. F. diagnostique. ] Pertaining to, or furnishing, a diagnosis; indicating the nature of a disease. [ 1913 Webster ]
n. The mark or symptom by which one disease is known or distinguished from others. [ 1913 Webster ]
v. t. & i. [ From Diagnostic. ] To make a diagnosis of; to recognize by its symptoms, as a disease. [ 1913 Webster ]
n. That part of medicine which has to do with ascertaining the nature of diseases by means of their symptoms or signs. [ 1913 Webster ]
His rare skill in diagnostics. Macaulay. [ 1913 Webster ]