馬車前端的橫木
Swingletree \Swin"gle*tree`\, n. [So named in allusion to its swinging. See {Swingle}, v. i., and cf. {Swingtree}.] A whiffletree, or whippletree. See {Singletree}.
swingletree n : a crossbar that is attached to the traces of a draft horse and to the vehicle or implement that the horse is pulling [syn: {whiffletree}, {whippletree}]