check.rein
n.（名词）A short rein that extends from a horse`s bit to the saddle to keep the horse from lowering its head.马缰绳：系于马的挽具与马鞍之间防止马低头的一种短缰绳A rein joining the bit of one of a span of horses to the driving rein of the other horse.缰绳：系于共轭马中一匹的挽具与其它马的缰绳之间的缰绳
