Dreaming
Our reality making engine during sleep, not using the information coming in through the senses to shape our experience and instead using what already has experienced, confronting you with a clearer or more abstract version of your positive and negative encounters. Coming at you with an intensity which is in every day life blended out/ dimmed down by your persons tunnel of attention. This subconscious stream of manifesting information could even contain information of dimensional layers we normally not have access to at all..
That would be my spontenous definition.