Structuralism is a mode of knowledge that focuses on relationships within systems, identifying meaning through structures rather than isolated individual objects. It originated in the early 1900s with Ferdinand de Saussure and was later developed by figures like Claude Lévi-Strauss and challenged by Noam Chomsky. Semiotics, introduced by Charles Sanders Peirce, explores the relationship between signs and their meanings, emphasizing the importance of interpretation in understanding signification.