Definition of "nocturne"

He [James Abbott McNeill Whistler] was then asked for his definition of a Nocturne: “I have perhaps, meant rather to indicate an artistic interest alone in the work, divesting the picture from any outside sort of interest which might have been otherwise attached to it. It is an arrangement of line, form, and colour first, and I make use of any incident of it which shall bring about a symmetrical result. Among my works are some night pieces; and I have chosen the word Nocturne because it generalises and simplifies the whole set of them.”

1908, E[lizabeth] R[obins] Pennell with J[oseph] Pennell, The Life of James McNeill Whistler, London: W[illiam] Heinemann; Philadelphia, Pa.: J. B. Lippincott Company

When John Ruskin, a sort of pope among the art critics of the time, was faced with [James Abbott McNeill] Whistler’s canvases at the opening exhibition of The Grosvenor Gallery in 1877, he was so outraged that he attacked Whistler in a review, charging him with wilful imposture for “flinging a pot of paint in the public's face.” It seems that Ruskin's main target was Whistler’s Nocturne in Black and Gold: The Falling Rocket (1875).

1996, Peter Wagner, “Oscar Wilde’s ‘Impression du matin’ – an Intermedial Reading”, in Icons – Texts – Iconotexts: Essays on Ekphrasis and Intermediality [European Cultures; 6], Berlin, New York, N.Y.: Walter de Gruyter, page 287

“My tastes,” he said, still smiling, “incline me to the garishly sunlit side of this planet.” And, to tease her and arouse her to combat: “I prefer a farandole to a nocturne; I’d rather have a painting than an etching; Mr. Whistler bores me with his monochromatic mud; I don’t like dull colours, dull sounds, dull intellects; […].”

1907 August, Robert W[illiam] Chambers, chapter VIII, in The Younger Set, New York, N.Y.: D. Appleton & Company

For all its grace, charm, and apparent simplicity, [Frédéric] Chopin’s Nocturne in E♭ major, Op. 9, No. 2, poses fundamental problems on close inspection. The fact that so many analyses of the piece – including those of Heinrich Schenker and Felix Salzer – fail to explain certain idiosyncratic aspects, in particular an unusual distribution of structural weight, gives some indication of the Nocturne’s complexities at a profound level.

1999, John Rink, “‘Structural Momentum’ and Closure in Chopin's Nocturne Op. 9, No. 2”, in Carl Schachter, Hedi Siegel, editors, Schenker Studies 2, Cambridge: Cambridge University Press, page 109

The vocal nocturne, in other words, turns out to be no easier a genre to define than the piano nocturne. But its ambiguities are nevertheless helpful in making sense of those of the piano nocturne.

2004, Halina Goldberg, editor, The Age of Chopin: Interdisciplinary Inquiries, Bloomington, Indianapolis, In.: Indiana University Press, page 222