Wiktionary
power nap
alt. A short sleep taken in the daytime in order to refresh a person and generally terminated before deep sleep begins so as not to leave the sleeper drowsy. n. A short sleep taken in the daytime in order to refresh a person and generally terminated before deep sleep begins so as not to leave the sleeper drowsy.
Wikipedia
Power nap
A power nap is a short sleep which terminates before the occurrence of deep sleep or slow-wave sleep (SWS), intended to quickly revitalize the subject. The expression was coined by Cornell University social psychologist James Maas.
Usage examples of "power nap".
He said he would pluck some berries to fill their stomachs while they waited for the snake to finish his power nap.