logical constant

A term used in formal logic, and often encountered in SEMANTIC theory, for those LEXICAL items which are considered part of the general FORM of an argument. The exact definition and membership of the set of logical constants is a matter of some debate, but it is typically understood to include at least the TRUTH FUNCTIONAL CONNECTIVES and QUANTIFIERS. In MODEL-THEORETIC SEMANTICS, logical constants are those EXPRESSIONS whose SEMANTIC VALUE does not vary from MODEL to model.