Sentence:  In mid-December [...], the French succeeded in storming the half-ruined outwork of the St Laurent <WSD>lunette</WSD> and advancing to a position immediately beneath the walls with their breaching batteries. 
Meaning of the word marked with <WSD> tags:  A field work consisting of two projecting faces forming a wedge each of which extends from one of two parallel flanks. (from 18th c.)