unihemispheric slow-wave sleep

American  

[yoo-nee-hem-i-sfeer-ik sloh-weyv sleep] / ˈyu niˌhɛm ɪˈsfɪər ɪk ˈsloʊˈweɪv ˈslip /

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

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Etymology

Origin of unihemispheric slow-wave sleep

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