clerestory
Concise Oxford English Dictionary © 2008 Oxford University Press:
clerestory /ˈklɪəˌstɔːri/ (US also clearstory)
▶noun (pl. clerestories)
- 1 the upper part of the nave, choir, and transepts of a large church, containing a series of windows.
- 2 a raised section of roof running down the centre of a railway carriage, with small windows or ventilators.
'clerestory' also found in these Oxford entries:

