The meaning of a string in some language, as opposed to syntax which describes how symbols may be combined independent of their meaning. The semantics of a programming language is a funCTIon from programs to answers. A program is a closed term and, in praCTIcal languages, an answer is a member of the syntaCTIc category of values. The two main kinds are {denotational semantics} and {operational semantics}. (1995-06-21)