IPA: /ˌmækɪkəˈleɪʃən/
KK: /mɑːˌkɪkəˈleɪʃən/
A structure at the top of a castle wall that has openings for dropping objects on enemies below, often supported by arches.
The castle's machicolation allowed defenders to attack invaders from above.
Machicolation → It is formed from "machi" (from Old French *machicoler*, meaning to provide with machicolations) and "-lation" (a suffix indicating the action or process). The word refers to the architectural feature of projecting parapets with openings for dropping missiles on attackers below.
Imagine a castle with a 'projecting' feature ('machi') that allows defenders to drop things on enemies below — that's what machicolation means.
No commonly confused words.