crupper

1. Her ears were very wide apart, her saddle deep, a fine head marked with a black star, a very long neck, strongly articulated knees, prominent ribs, oblique shoulders and a powerful crupper.
   两只耳朵分得很开，脊梁凹。细长的头上有一颗黑星，脖子很长，膝骨非常突出，肋宽，肩斜，臀部壮大。

noun

1. a strap from the back of a saddle passing under the horse's tail