is 4 hours still a nap?

I just took a 4 hour nap from 3 pm to 7 pm (which is now) and I wonder, is my 4 hour nap still a nap? During our IB (International Baccalaureate) information night, Mr. _______, the IB coordinator at our school, said: "4 hour is not a nap." because the IB students messes up their time by taking naps after school, then staying up really late.

Anyways, the main point is: is 4 hours still a nap? Or is it a sleep?

Sometimes I take 5 or 6 hours 'naps' as well. If 4-6 hours aren't naps anymore, then what are they? You can't exactly say I'm just sleeping because I know I will wake up later and I'm not completely at ease because I know I have to wake up sooner or later. Hmmm...

I shall continue to wonder about this.

Pockymeji.