Pragmatics is generally the study of natural language understanding, and specifically the study of how context influences the interpretation of meanings. It is a subfield of linguistics.
Context here must be interpreted as situation as it may include any imaginable extralinguistic factor, including social, environmental, and psychological factors.
Methodology and presuppositions
Pragmatics is interested predominantly in utterances, made up of sentences, and usually in the context of conversations.
A distinction is made in pragmatics between sentence meaning and speaker meaning. Sentence meaning is the literal meaning of the sentence, while the speaker meaning is the concept that the speaker is trying to convey.
The ability to understand another speaker's intended meaning is called pragmatic competence.
According to Charles W. Morris, Pragmatics tries to understand the relationship between signs and interpretations, while semantics tends to focus on the actual objects or ideas that a word refers to, and syntax (or "syntactics") examines the relationship between signs.
Topics in pragmatics