Denotational Semantics is a formal method for defining the meaning of programming languages. It assigns mathematical objects, called denotations, to phrases in a language, allowing for a precise understanding of their behavior. This approach focuses on the meaning of expressions rather than their execution, providing a clear framework for reasoning about programs. By using domain theory, denotational semantics maps syntactic constructs to their meanings in a structured way. This helps in analyzing and proving properties of programs, such as correctness and equivalence. Overall, it serves as a foundation for understanding how programming languages function at a deeper level.