A lucid dream is a dream in which one is aware that one is dreaming. The term was coined by the Dutch psychiatrist and writer Frederik (Willem) van Eeden (1860–1932).
A lucid dream can begin in one of two ways. A dream-initiated lucid dream (DILD) starts as a normal dream, and the dreamer eventually concludes it is a dream, while a wake-initiated lucid dream (WILD) occurs when the dreamer goes from a normal waking state directly into a dream state, with no apparent lapse in consciousness.
Lucid dreaming has been researched scientifically, and its existence is well established