In the R&K standard, NREM sleep was divided into four stages, with slow-wave sleep comprising stages 3 and 4. In stage 3, delta waves made up less than 50% of the total wave patterns, while they made up more than 50% in stage 4. Furthermore, REM sleep was sometimes referred to as stage 5.
Freebase(0.00 / 0 votes)Rate this definition: Turret. In architecture, a turret is a small tower that projects vertically from the wall of a building such as a medieval castle. Turrets were used to provide a projecting defensive position allowing covering fire to the adjacent wall in the days of military fortification.
any structure, contrivance, or object that resembles or suggests a tower. a tall, movable structure used in ancient and medieval warfare in storming a fortified place. a tall, vertical case with accessible horizontal drive bays, designed to house a computer system standing on a desk or floor. Compare minitower.