slumber
n. C / Un. a deep, peaceful sleep. It is a more poetic or old-fashioned way to talk about sleeping.
n. a state of sleep, particularly one that is deep, quiet, or undisturbed. Often carries a literary or poetic tone in modern usage.
The baby fell into a deep slumber after her meal.
The heavy curtains blocked out the morning sun, allowing him to remain in a peaceful slumber until noon.
The ancient forest seemed to be in a deep winter slumber, with no sound breaking the silence of the snow-covered pines.
From Middle English slombren, slomren, frequentative of Middle English slummen, slumen (“to doze”), probably from Middle English slume (“slumber”), from Old English slūma, from Proto-Germanic slūm- (“slack, loose, limp, flabby”), from Proto-Indo-European (s)lew- (“loose, limp, flabby”). Cognate with West Frisian slommerje, slûmerje (“to slumber”), Dutch sluimeren (“to slumber”), German schlummern (“to slumber, doze”), Swedish slummer (“to slumber”). By surface analysis, sloom + -er.
Often used in the singular with an adjective like 'deep', 'peaceful', or 'restless'.