Merriam-Webster Collegiate Dictionary - semantics

 noun plural but singular or plural in construction  Date: 1893  1. the study of meanings:  a. the historical and psychological study and the classification of changes in the signification of words or forms viewed as factors in linguistic development  b.  (1) semiotic  (2) a branch of semiotic dealing with the relations between signs and what they refer to and including theories of denotation, extension, naming, and truth  2. general ~  3.  a. the meaning or relationship of meanings of a sign or set of signs; especially connotative meaning  b. the language used (as in advertising or political propaganda) to achieve a desired effect on an audience especially through the use of words with novel or dual meanings