Sleep taken before midnight. Those who habitually go to bed, especially during youth, after midnight, are usually pale and more or less haggard.
“Would I please to remember that I had roused him up at night ... [in] his beauty sleep.” —Blackmore: Lorna Doone, chap. 64.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894
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