Sentence:  Lennan held the black horse — a bizarre little beast, all fire and whipcord, with a skin like satin, liquid eyes, very straight hocks, and a thin <WSD>bangtail</WSD> reaching down to them. 
Meaning of the word marked with <WSD> tags:  The tail of a horse or cow, allowed to grow out and then trimmed horizontally so as to form a tassel; a horse or cow having such a tail.