1. a structured entity consisting of various components that interact to perform one or more functions. Business, industrial, and service entities are constituted in this way.

2. in Gestalt psychology, an integrated perception composed of various components that appear together as a single whole, such as a face. See gestalt principles of organization.

3. in memory research, the structure discovered in or imposed upon a set of items in order to guide memory performance.

4. in Piagetian theory, the coordinated biological activities of the organism as determined by genetic factors, interactions with the environment, and level of maturation. Inherent in this theory is the concept that every intellectual operation is related to all other acts of intelligence. Such mental processes become increasingly organized, initially developing through reflex behavior and responses to immediate stimulation and gradually becoming self-sustaining, self-generating, and capable of reflecting the child’s own thoughts. See functional invariant. —organizational adj.