The missing word and the answer is music.
James Abbott Mcneill Whistler was a leading proponent of the credo "art for art's sake". HIs revolutionary methods changed existing approaches to pastel, oil paint, etching, watercolor, and also interior design. Finding a parallel between painting and music, he entitled many of his works "harmonies", "nocturnes", and "harmonies" that emphasizes primacy of tonal harmony.
