(1) The theory that parts of a whole are in intimate interconnection, such that they cannot exist or be understood independently of the whole. (von Bertalanffy 1968)
(2) To take a Holistic view of a situation. (von Bertalanffy 1968)
(1) and (2) von Bertalanffy, L. 1968. General system theory: Foundations, development, applications, Revised ed. New York, NY: Braziller.
The term "holistic " is used to describe an approach based on holism.