Meanings of castellated structure in английском

The crowning shaft is missing here, but a castellated structure of red rock suitably dominates it.

The old grey castellated structure, erected in 1837, stood on the east side of the Square until 1894.

In ten minutes there was another smoke signal, and a great cloud over the castellated structure on the other side of the bay.

They consisted of an enormous towering fortress at the stern; a castellated structure almost equally massive in front, with seats for the rowers amidships.