A head-dress, apparently a kind of cap or veil, worn in the sixteenth and seventeenth centuries.(noun)
The Century Dictionary (Public Domain)
Use "nightrail" in a sentence
"Does it not look as if she would have been an useful creature in the days of nightrail and notableness, had she been a wife in good time?"
"Jack instantly panned his gaze over her, taking in the soft folds of her nightrail, the plaid shirt that sagged off her gently sloping shoulders … and the fall of her wealth of hair."
"The cloak was of the latest mode, very wide and open at the neck and shoulders, and beneath the mantle I caught more than a glimpse of the laced white nightrail and the fine sloping neck."