Daydreaming is a short-term detachment from one's immediate surroundings. During a daydream, a person's contact with reality is blurred. External reality is second to a visionary fantasy.
There are many types of daydreams, and there is no agreed definition. However, the characteristic that is common to all forms of daydreaming is a mild separation from the person's surroundings. Daydreams are under conscious control, so they differ from dreams, but they do have a kind of dream-like fantasy quality. Although daydreaming in children may be frowned upon by parents and teachers, it seems quite normal. There is evidence which suggests daydreaming is associated with mental health and stability.