Define Stay at Home Parent?

Can you please help me? What is a stay at Home Parent? Can you still have your kids in Daycare even part time and me a stay at home parent? I was reading about a daddy that was telling the world how he was a stay at home father in his Christmas Card. I thought cool for him someone I know I could talk with about Stay at home issues. I emailed him and we started talking, He maybe has the kids 3 to 4 hours by himself. He still takes the kids to daycare everyday. So does he work? Go to school, maybe remodel the house? NOPE, he uses that time to get stuff done!! Like what? Would I love to have a few hours alone each day? Sure and often when the wife and son go to bed I get this. The question is? Is this a stay at home parent? Why does this piss me off?