1620s (adjective and noun), from Greek diagnostikos "able to distinguish," from diagnostos, verbal adjective from diagignoskein (see diagnosis). Related: Diagnostics.
diagnostic di·ag·nos·tic (dī'əg-nŏs'tĭk)
adj.
Of, relating to, or used in a diagnosis.
Serving to identify a particular disease; characteristic.
diagnostics The art or practice of medical diagnosis.
A symptom or a distinguishing feature serving as supporting evidence in a diagnosis.
An instrument or a technique used in medical diagnosis.