Structuralism (structural anthropology) is an approach in anthropology which examines the patterns and structure of a culture in its entirety, instead of isolating specific phenomenon within that culture for purposes of comparison (which is what functionalism does).  Structuralism inspects the relationships within a cultural network for a more complete understanding of that culture.  Claude Lévi-Strauss, in particular, was interested in social mores and taboos, how they became integral parts of a culture and what their purposes indicated about that culture specifically and mankind in general.