diagnostic
1. di.ag.nos.tic \-'na:s-tik\ \-ti-k(*-)le-\ aj : of or relating to diagnosis - di.ag.nos.ti.cal.ly av 2. diagnostic \-.na:s-'tish-*n\ n 1: the art or practice of diagnosis - often used in pl. 2: a distinguishing mark - di.ag.nos.ti.cian n