bridle

n. 1 headgear for controlling a horse, including reins and bit. 2 restraining thing. v. (-ling) 1 put a bridle on. 2 curb, restrain. 3 (often foll. By up) express anger, offence, etc., esp. By throwing up the head and drawing in the chin. [old english]

n. The head gear with which a horse is governed and restrained, consisting of a headstall, a bit, and reins, with other appendages.