noun
headstall, martingale, and crupper (as a set)
Specialized equestrian term referring to the three connected pieces of horse tack: the headstall (面繋), martingale (胸繋), and crupper (尻繋). Rare outside historical or technical contexts.
古い馬具の図録には、三懸の各部の名称が記されている。
In old horse tack catalogs, the names of each part of the sangai are recorded.
Compound of 三 (three) and 懸/繋 (hang/connect), referring to the three connected pieces of horse tack. The exact historical derivation is uncertain.