checkrein

詳細解釋：

check.rein

n.（名詞）
A short rein that extends from a horse`s bit to the saddle to keep the horse from lowering its head.
馬韁繩：繫於馬的挽具與馬鞍之間防止馬低頭的一種短韁繩
A rein joining the bit of one of a span of horses to the driving rein of the other horse.
韁繩：繫於共軛馬中一匹的挽具與其它馬的韁繩之間的韁繩