In many modern corporate workplaces, a<unk>  is where an employee does not come to work and takes a sick<unk>  for reasons other than physical illness. Some people may consider a<unk>  to be when someone simply does not feel like coming in to work, but the most accurate use of this term is related to a true need to have a<unk>  to reset one's<unk><unk>  rather than a desire to skip work.
Mental health day
Nightmare
Sleep onset
Sleep sex
Morning report 
Clinical clerkship
Child development stages
Nightingale ward