[di.ag.nos.tic] also di.ag.nos.ti.cal adj (1625) 1 a: of, relating to, or used in diagnosis b: using the methods of or yielding a diagnosis
2: serving to distinguish or identify -- di.ag.nos.ti.cal.ly adv
[2]diagnostic n (1625) 1: the art or practice of diagnosis--often used in pl.
2: a distinguishing mark -- di.ag.nos.ti.cian n