Castellated comes from Medieval Latin castellātus (built like a castle), from Latin castellum (fort), and describes buildings or objects with battlement-like features.
Having battlements or turrets like a castle; built in the style of a castle
Castellated entered English in the early 17th century from Medieval Latin castellātus, meaning 'built like a castle' or 'furnished with turrets,' from Latin castellum (fort, castle), the diminutive of castrum (fortified place). The suffix -ātus marks the past participle / adjectival form. The word describes both genuine fortifications and the decorative application of castle-like features (battlements, crenellations, turrets) to buildings that serve no military purpose. The Gothic Revival of the 18th and 19th
In mechanical engineering, a castellated nut has slots cut around its rim that look like the merlons and crenels of a castle wall. A cotter pin passes through these slots and the bolt to prevent the nut from turning — medieval fortification terminology repurposed for industrial hardware.