The term somnambulism comes from the Latin words for sleep (somnus) and walking (ambulus). A typical sleepwalking episode is rather short. Sleepwalkers may simply appear awake, or exhibit complicated activity such as driving a car, while asleep.
Sleepwalking (also called noctambulism or somnambulism), under the larger category of parasomnia, is a sleep disorder where the sufferer engages in activities that are normally associated with wakefulness while asleep or in a sleeplike state. Sleepwalkers (somnambulists) are aroused out of their deep sleep during motor activity, which usually includes, but is not limited to, walking.
A sleepwalker can go back to sleep some place other than bed, depending on how far he or she has walked. Sleepwalkers are usually unaware of their activity. Some cases of autonomic (independently functioning) behavior that occur with sleepwalking involve dressing and even eating.
What causes sleepwalking is not known, though most people have sleepwalked on at least one occasion. Sleepwalking poses no serious health threat to those who experience it, although the risk of injury, however minor, is a matter of concern.