The philosophical and scientific study of meaning.
Sometimes considered to be the same thing as semiotics, semology, or semasiology, which have overlapping meanings. This is a relatively new field of study, and several pioneers who largely worked independently of one another each felt the need to coin a new name for the new discipline, resulting in a variety of terms for the same subject.
The word semantics is widely preferred as the name for the doctrine of meaning, particularly linguistic meaning. Semiotics denotes the study of sign-using behaviour in general.
-- Based on britannica.com entry