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.
A battlement in defensive architecture, such as that of city walls or castles, comprises a parapet (i.e. a defensive low wall between chest-height and head-height), in which rectangular gaps or indentations occur at intervals to allow for the discharge of arrows or other missiles from within the defences.n medieval England a licence to crenellate granted the holder permission to fortify their property. Such licences were granted by the king, and by the rulers of the counties palatine within their jurisdictions, i.e. by the Bishops of Durham and the Earls of Chester and after 1351 by the Dukes of Lancaster.