Sentence:  His forefathers had been, as a rule, professional men&mdash;physicians and lawyers; his grandfather died under the walls of Chapultepec Castle while twisting a tourniquet for a cursing <WSD>dragoon</WSD>; an uncle remained indefinitely at Malvern Hill;nb.... 
Meaning of the word marked with <WSD> tags:  A horse soldier; a cavalryman, who uses a horse for mobility, but fights dismounted.