Anyone know where to know the meaning of DREAM?

Do u know how to describ the meaning of Dream?

I had a dream...really clear dream...
Normally, the dream will forgottable when u wake up from dream...but this few days dream are still can remember what is happend inside the dream...amazing...

Anywhere, i just wanna to know, If u wanna fight sumthing inside ur dream and u fail...then in reality got any affect?

God Bless me...