Sentence:  They called each other by their Christian name, were always arm in arm when they walked, pinned up each other's <WSD>train</WSD> for the dance, and were not to be divided in the set [...]. 
Meaning of the word marked with <WSD> tags:  The elongated back portion of a dress or skirt (or an ornamental piece of material added to similar effect), which drags along the ground. (from 14th c.)