The upper parts of walls carried on arcades or colonnades in the nave, choir or transepts of a church or hall, rising higher than the lean-to roofs of the aisles and pierced with windows to allow light to penetrate.
![St Nicholas' Church, Blakeney, showing the two towers, the seven lancet east window and the clerestory.](http://hbsmrgateway2.esdm.co.uk/norfolk/DataFiles/FullImages/688.jpg)
St Nicholas' Church, Blakeney, showing the two towers, the seven lancet east window and the clerestory. (© NCC)