noun
headstall; headgear (for a horse)
Part of a horse's bridle or halter that goes over the head, specifically the crownpiece or headstall. Domain-specific equestrian term.
馬に面繋を付けるときは、耳を傷つけないように注意が必要だ。
When putting the headstall on a horse, care must be taken not to hurt its ears.
頭絡 is a more general term for a horse's bridle or headgear, while 面繋 specifically refers to the crownpiece or headstall part.
Compound of 面 (omo, 'face') + 繋 (kai, 'tether' or 'connect'), referring to the part of the bridle that goes over the horse's face. The exact historical derivation is uncertain.