Semiotics

Semiotics, also known as semiotic studies, is the study of the usage and interpretation of signs and symbols - either by making them or the study of meaningful communication. This includes study of the linguistic uses of analogy, allegory, metonymy, metaphor, symbolism, signification, and communication in literature. Semiotics explores the study of signs and symbols as significant parts of human communications. Different from linguistics, semiotics also studies non-linguistic sign systems. Examples of non-linguistic sign systems are things like gestures and facial expressions.

For instance. someone rubbing their temples usually indicates that they have a headache while someone frowning and glaring indicates anger.