Pathognomonic \Pa*thog`no*mon"ic\, a. [Gr. ? skilled in judging of diseases; ? a disease + ? skilled: cf. F. pathognomonique. See {Gnomic}.] (Med.) Specially or decisively characteristic of a disease; indicating with certainty a disease; as, a pathognomonic symptom. The true pathognomonic sign of love jealousy. --Arbuthnot.