se·mi·ot·ics

– noun
1. the study of signs and symbols as elements of communicative behavior; the analysis of systems of communication, as language, gestures, or clothing.
2. a general theory of signs and symbolism, usually divided into the branches of pragmatics, semantics, and syntactics.

prag·mat·ics

– noun
1. the branch of semiotics dealing with the causal and other relations between words, expressions, or symbols and their users.
2. the analysis of language in terms of the situational context within which utterances are made, including the knowledge and beliefs of the speaker and the relation between speaker and listener.
3. practical considerations.

se·man·tics

– noun
1. a. the study of meaning.
b. the study of linguistic development by classifying and examining changes in meaning and form.
2. the branch of semiotics dealing with the relations between signs and what they denote.
3. the meaning, or an interpretation of the meaning, of a word, sign, sentence, etc.

syn·tac·tics

– noun
1. the branch of semiotics dealing with the formal properties of languages and systems of symbols.