Semantics is the study or use of meaning. Meaning can be interpreted variably, and use of meaning and expression alters according to context and usage.
The traditional form of semantics is the naturally understood meaning of words or forms of expression. This is a simple value system, applying a basal meaning to words or expressions.
That just means the words mean what they appear to mean, and have no other values or hidden meanings. It's really what you would reasonably expect a statement to mean. It's not the same as reading something literally, however. Language usage is rarely that simple, and modern languages are quite different from their original semantic bases.
The meaning of words changes, often drastically, and this is where the real study of Semantics is involved. Conversational language is usually comprised of common words and slang. Over time, language evolves, and some words develop meanings beyond their original usage. Slang often replaces other expressions.
The recent history of English is a case in point. We can easily read Charles Dickens, who used the literate modern English of his time. He, however, would find a lot of modern English unintelligible to the point of being meaningless.
Mass media, like advertising or TV, adds words and concepts to the language on a regular basis. Anything, from a brand name to a scientific concept, can work its way into language and be used in a range of new ways. The word 'nano', for example, was an obscure term in science until the 1990s. It's now part of the linguistic furniture, an extra description of anything small.
Connotative meaning is the complex form of semantics. It's one of the growing areas of semantic study as a result of the continual input of new terms into language. Connotations are created by associations of words, and the inevitable result of massive amounts of new expressions has been an equally large explosion in the development of connotation in language.
Literature is largely connotative usage of language. Meanings are extended by connotation and association of ideas.
Examples of connotative semantics illustrate the levels of complex meaning. The connotative semantic elements are in bold:
It is a good day to die. (Crazy Horse)
All the world's a stage, and all the men and women merely players. (Shakespeare)
And a thousand slimy things lived on and so did I. (Coleridge)
All is for the best in this best of all possible worlds. (Voltaire)
Each connotative word adds associations. The use of compound connotative words extends meanings far outside the literal translation.
Symbols and semantics
Usage can also include the use of terms as symbols. A word or a character in a book can be given a connotation, and used as a symbolic reference. The character 'Rosebud' in Citizen Kane is an example, the meaning being transferred to a symbolic term. The meanings of references to the symbol, therefore, are based on the value of the symbol.