A dream is a release of revelation, natural or spiritual, that comes at a time when your body is at peace and you are settled. Sometimes this is the only way God can communicate with you, because your soul is quiet enough for the Lord to speak deeply into your spirit. Dreams are formed in the subconscious mind of man or woman based on images and symbols which are unique to the individual, depending on his/her background, experience and current life circumstances. Dreams are given first to our subconscious minds before being perceived by our conscious minds.
Visions is to imagine you are having a dream, but you are awake. It seems if you are entering a different reality, since we are seeing images of items and events with our spiritual eyes what is not there in the physical.
It is important for us to exercise discernment in determining the source of dreams and visions.