Battlement - Things Learned while reading "The Hound of the Baskervilles" - Sherlock Holmes

"From this central block rose the twin towers, ancient, crenelated, and pierced with many loopholes."

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Battlement - Wikipedia, the free encyclopedia: "A battlement (also called a crenellation) in defensive architecture, such as that of city walls or castles, comprises a parapet (i.e. a short wall), in which portions have been cut out at intervals to allow the discharge of arrows or other missiles. These cut-out portions form crenels (also known as carnels, embrasures, loops or wheelers)."
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