Dictionary.net

• A picture of a night scene; a dreamy, sentimental, musical composition appropriate to the night; a serenade.

1919 - The Winston Simplified Dictionary
By William Dodge Lewis, Edgar Arthur Singer

• Art. A painting representing a night-scene.

• A dreamy, sentimental composition appropriate to the evening or night.

1919 - The Concise Standard Dictionary of the English Language
By James Champlin Fernald