unihemispheric slow-wave sleep

[ yoo-nee-hem-i-sfeer-ik sloh-weyv sleep ]

noun

, Physiology.

1. a mode of sleep behavior, common for certain species of birds and aquatic mammals, in which one cerebral hemisphere is deeply asleep while the other is completely awake: Often, unihemispheric slow-wave sleep, with one eye closed and one eye open, is mingled with occurences of bihemispheric slow-wave sleep, but for cetaceans, including dolphins and whales, only unihemispheric sleep occurs. : USWS

Word History and Origins

Origin of unihemispheric slow-wave sleep¹

First recorded in 1980–85; uni- ( def ) + hemispheric ( def )