1. a relatively stable arrangement of elements or components organized to form an integrated whole. Structure is often contrasted with function to emphasize how something is organized or patterned rather than what it does. See also bidirectionality of structure and function.

2. a complex entity consisting of organized components.

3. according to Jean Piaget, any of the entities that together comprise the enduring knowledge base by which children interpret their world. A structure is equivalent to a scheme. —structural adj.