Gestalt psychology vs Gestalt principle of organization

Gestalt psychology and Gestalt principle of organization both are nouns.

Word	Noun	Adjective	Verb	Adverb
Gestalt psychology	Yes	No	No	No
Gestalt principle of organization	Yes	No	No	No

Gestalt psychology (noun)	Gestalt principle of organization (noun)
(psychology) a theory of psychology that emphasizes the importance of configurational properties	a principle of Gestalt psychology that identifies factors leading to particular forms of perceptual organization