machicolation
Concise Oxford English Dictionary © 2008 Oxford University Press:
machicolation/-ˈleɪʃ(ə)n/
▶noun (in medieval fortifications) an opening between the supporting corbels of a projecting structure, through which stones or burning objects could be dropped on attackers.
■ a projecting structure containing machicolations.
'machicolation' also found in these Oxford entries:

