A nap is a short period of sleep, typically taken during daylight hours as an adjunct to the usual nocturnal sleep period. Naps are most often taken as a response to drowsiness during waking hours. Cultural attitudes toward napping during the work day vary; children and the elderly are often expected to nap during the day and are provided with designated periods and locations to do so, but most working adults are not and napping on the job is widely considered unacceptable. On the other hand, many cultures (especially those in hot climates) serve their largest meals at midday, with an official allowance for a nap period (siesta) afterwards before returning to work.

Read more about Nap:  Negative Effects, Benefits, Power Nap, Caffeine Nap, Systematic Napping As A Lifestyle