Definition of Gesamtkunstwerk from wiki: (translated as total work of art, ideal work of art, universal artwork, synthesis of the arts, comprehensive artwork, all-embracing art form, or total artwork) is a work of art that makes use of all or many art forms or strives to do so. The term is a German word, which has come to be accepted in English.The term was first used by the writer and philosopher K.F.E. Trahndorff in an essay in 1827. The German opera compose Richard Wagnerr used the term in an 1849 essay. It is unclear whether Wagner knew of Trahndorff’s essay. The word has become particularly associated with Wagner’s aesthetic ideals.

Definition of Gesamtkunstwerk from Artnet: [Ger.: complete, unified or total work of art].Term first used by Richard Wagner in Das Kunstwerk der Zukunft (1849) to describe his concept of a work of art for the stage, based on the ideal of ancient Greek tragedy, to which all the individual arts would contribute under the direction of a single creative mind in order to express one overriding idea. However, the term is applied retrospectively to projects in which several art forms are combined to achieve a unified effect, for example Roman fora, Gothic cathedrals and some Baroque churches and palazzi.