English

Noun

dead sleep ‎(usually uncountable, plural dead sleeps)

1. The first sleep of the night in a biphasic sleep pattern.
   • 2001, A. Roger Ekirch, Sleep We Have Lost: Pre-Industrial Slumber in the British Isles, The American Historical Review, Volume 106, Number 2 (April 2001), American Historical Association, page 364:

     Until the close of the early modern era, Western Europeans on most evenings experienced two major intervals of sleep bridged by up to an hour or more of quiet wakefulness. […] The initial interval of slumber was usually referred to as “first sleep,” or, less often, “first nap” or “dead sleep.”

Synonyms

• (first sleep of the night): first sleep

Antonyms

• morning sleep