Triangular outworks situated in the moats of fortifications, and that resemble bastions with a crescent-shaped gorge, constructed to protect a bastion or curtain. The term is often used interchangeably with 'ravelins'. Historically there may have been distinguishing characteristics between ravelins and demi-lunes in the Italian school of fortification design, but in the modern era these terms are most often used synonymously. (en)
In de hoofdgracht gelegen 'buitenwerken' van vestingen, dienende tot dekking van 'saillanten' van 'bastions' of 'ravelijnen'. (nl)