It’s about time. We are now on Instagram!
1640s (implied in pathognomonical), from patho- "disease, suffering" + Greek gnomonikos "able to judge," from gnomon "one who knows" (see gnomon).
pathognomonic pa·thog·no·mon·ic (pə-thŏg'nə-mŏn'ĭk, pāth'əg-nō-)adj. Characteristic or symptomatic of a particular disease or condition.