Emily Dickinson Lexicon

PA-THOG-NO-MON'IC, a. [Gr. παθογνωμονικος, παθος, passion or suffering, and γνωμων, from γινωσκω, to know.]

Indicating that which is inseparable from a disease, being found in that and in no other; hence, indicating that by which a disease may be certainly known; characteristic, as pathognomonic symptoms.