Wiktionary
demilunes
n. (plural of demilune English)
Usage examples of "demilunes".
Other than the two demilunes outside, the four corner bastions, and the ramparts themselves, that's the setup aboveground.
They had enclosed this peninsula in a modern sort of slope-sided wall, a couple of miles in circuit, and erected noble bulwarks and demilunes at its corners, rendering it impregnable to land assault by Dutch, Chinese, or native legions.
There are some weak points, but I have reinforced them with demilunes and batteries.