Noun
English Wikipedia has an article on:power napWikipedia
power nap (plural power naps)
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.
I'm a fan of the power nap. About twice a week, I'll stretch out on a little couch in my office for 20 minutes. I don't need a wake-up call; I pop right up, feeling refreshed. Tim Finchem