- A theory of sociology that views elements of society as part of a cohesive, self-supporting structure.
- (biology) A school of biological thought that deals with the law-like behaviour of the structure of organisms and how it can change, emphasising that organisms are wholes, and therefore that change in one part must necessarily take into account the inter-connected nature of the entire organism.
- (linguistics) The theory that a human language is a self-contained structure related to other elements which make up its existence.
- (psychology) A school of thought that focuses on exploring the individual elements of consciousness, how they are organized into more complex experiences, and how these mental phenomena correlate with physical events.
- (mathematics) In the philosophy of mathematics, a theory that holds that mathematical theories describe structures, and that mathematical objects are exhaustively defined by their place in such structures.