well its something like your able to control your actions,and things you do in dreams.I'll get a definition,somewhere.

this one might suffice.


1.1. What is Lucid Dreaming?
Lucid Dreaming is knowing that you are dreaming while you are doing it. When you know that you
are dreaming, you can also alter the dream course. And with practice you can also develop full
control over your dream, you will be able to create and change the environment and change your
own appearance. It will be you that are in control of the dream scenario. You can do whatever
you want to do. Live out your wildest fantasy, or just sit down and chit chat with someone. You
should also be open for the possibility to share dreams and travel in time and space when you
develop adequate control over your dreams. The word Lucid means that you have a clear and full
consciousness. And believe me when I say that Lucid Dreaming can be much more fun than waking
reality.

Im no expert or anything,this is where I got it from.

http://www.faqs.org/faqs/dreams-faq/lucid-dreaming-faq/