Is it possible to know you're in a dream?

it means you're very smart because if you Dream while you know your in it, it's a proven fact because the brain still works when you're asleep but the rest of the body doesn't, or you get many dreams that you're so used to it you kind of feel like you're in your imagination...

The phenomenon of realizing you are in a dream while dreaming is called "lucid dreaming." It does not "mean" anything in particular, other than the conscious mind has become active during the dream without fully awakening.