Night-dress

"Was your sister dressed?" "No, she was in her night-dress."

Source: tatoeba (6620960)

Or if, on the contrary, we had taken a fancy for the terrible, and made the lover of the new femme de chambre a professional burglar, who bursts into the house with his band, slaughters black Sambo at the feet of his master, and carries off Amelia in her night-dress, not to be let loose again till the third volume, we should easily have constructed a tale of thrilling interest, through the fiery chapters of which the reader should hurry, panting.

Source: wiktionary

“[…] You were very nearly dead to-night, Macumazahn.” / “Very nearly, indeed,” I answered, still panting, and arranging the rags of my night-dress round me as best I might.

Source: wiktionary

Then, with a nod to his brother and a short word of greeting to the dauphin and to the Duc du Maine, he swung his legs over the side of the bed, and sat in his long silken night-dress, his little white feet dangling from beneath it—a perilous position for any man to assume, were it not that he had so heart-felt a sense of his own dignity that he could not realise that under any circumstances it might be compromised in the eyes of others.

Source: wiktionary