I had no idea were to put this so sorry in advance if it’s in wrong place =\
I was just wonder what day dreaming was, I think I may be doing it all day everyday =O
When nothing interesting is going on I kind of space out and think of some fantasy senareo (Like attacking a castle) and after a couple minutes it just continues automaticly. It keeps like going back in time though and the same thing will happen, but a different way.
A daydream is what the tin says: a dream you have by daytime 
It can hardly be defined in other ways without losing in broadness of meaning, but for most, it’s letting their imagination flow while they usually detach themselves from what’s going on outside. It has varying degrees of “realness” for different people, depending on how vivid their imagination is (and yes, it’s “vivid” as if referring to dreams), and apparently it also has varying degrees of lucidness.
There’s a very interesting topic named Lucid DayDreaming, you can check that out for more info ^^