whiffletree
/ˈwɪf(ə)ltriː
/noun North American
A swingletree.The invention of the horse shoe, the whiffletree, and the spring carriage made travel easier....
- I had to get out and let the whiffletrees loose, then the team managed to get out on solid ground.
- This works something like a hollow auger; it is used for cutting tenons on poles, shafts, whiffletrees, etc.
Origin
Mid 19th century: variant of whippletree.