1. The study of the symptoms or characteristics of a disease: Research in the area of pathognomy was in progress to find out the indications, features, and properties of disorders, infections, and illnesses.
2. The science of the signs by which human passions are indicated: Pathognomy includes the outward expression of a person's feelings.

Pathognomy is the study of passions and emotions. It refers to the expression of emotions that are indicated in the voice, gestures, and by features.

While physiognomy is used to predict the overall character of an individual, pathognomy is used to gain clues about the current character.

Physiognomy is based on shapes of the features, and pathognomy on the motions of the features.