If some one wakes up in the middle of the night and eat something and sleep again. What would that be called? Is their any formal name for it?

Lunch & Dinner!

 1. Dinner

2. Supper

And there's one more thing: 5 o'clock

Thank you! This whole post had been informative.

It's not breakfast.  However, breakfast food as a midnight snack can be yummy.