morning sleep

plural morning sleeps

1. uncountableusuallyThe second sleep of the night in a biphasic sleep pattern, after the watch.

   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 succeeding interval of slumber was called “second” or “morning” sleep.

   2001 April, A. Roger Ekirch, “Sleep We Have Lost: Pre-Industrial Slumber in the British Isles”, in The American Historical Review, volume 106, number 2, American Historical Association, pages 364–365

   Synonyms: next sleep, second sleep