Noun
headcollar (plural headcollars)
A bitless headpiece for leading or tying up a horse.
An underhalter is a lightweight halter or headcollar which is made with only one small buckle, and can be worn under a bridle for tethering a horse without untacking. Source: Internet
Halters main A halter (US) or headcollar (UK) (occasionally headstall) consists of a noseband and headstall that buckles around the horse's head and allows the horse to be led or tied. Source: Internet