n.a projecting parapet supported by corbels on a medieval castle; has openings through which stones or boiling water could be dropped on an enemy
英汉双解大词典
machicolation/məˌtʃɪkəʊˈleɪʃən/
1.
N（名词）
(esp in medieval castles) a projecting gallery or parapet supported on corbels having openings through which missiles could be dropped (在中世纪城堡的)堞口; 支撑在梁托上的突出的廊道或护墙，有开口，投射物可以从开口中扔进