A gestalt has two or more parts (like figure and ground) that are so integrated together that we perceive them as one object. Think of teaching "the whole child," and you have the idea behind gestalt.
The perception of oneness from many is the basis of gestalt. It derived from the 1890 German philosophy of Gestaltqualität, meaning "form or shape," which explored the idea of perception. For example, a picture might have several separate parts that work together to form one perceived image. The area of gestalt psychology developed in 1912, focusing on the various aspects of a person and how they combine into a whole that affects that person's relationship with his or her environment.