ma·chic·o·la·tion 
(mə-chĭk′ə-lāshən)
(mə-chĭk′ə-lāshən)n.
1.
a. A projecting gallery at the top of a castle wall, supported by a row of corbels and having openings in the floor through which stones and boiling liquids could be dropped on attackers.
b. One of these openings.
2. A row of small projecting arches used as an ornamental architectural feature.
machicolation