This study represents a contribution to the theory of meaning in natural language. It proposes a semantic theory containing a set of regular relational principles. These principles enable semantic theory to describe connections from the lexical reading of a word to its figurative contextual reading, from one variant reading of a polysemous lexical item to another, from the idiomatic to its literal reading or to the literal reading(s) of one or more of its component lexical items. Semiotic theory provides a foundation by supplying principles defining motivated expression-content relations for signs generally. The author argues that regular semantic relational principles must dervive from such semiotic principles, to ensures the psychological reality and generality of the semantic principles.