1. (noun)complex, composite a conceptual whole made up of complicated and related parts "the complex of shopping malls, houses, and roads created a new town"
2. (noun)complex, coordination compound a compound described in terms of the centralatom to which other atoms are bound or coordinated
4. (noun)building complex, complex a wholestructure (as a building) made up of interconnected or related structures
5. (adj)complex complicated in structure; consisting of interconnected parts "a complex set of variations based on a simple folk melody"; "a complex mass of diverse laws and customs"